src/core/qgsgeometry.cpp

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/***************************************************************************
  qgsgeometry.cpp - Geometry (stored as Open Geospatial Consortium WKB)
  -------------------------------------------------------------------
Date                 : 02 May 2005
Copyright            : (C) 2005 by Brendan Morley
email                : morb at ozemail dot com dot au
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include <limits>
#include <cstdarg>
#include <cstdio>
#include <cmath>

#include "qgis.h"
#include "qgsgeometry.h"
#include "qgsapplication.h"
#include "qgslogger.h"
#include "qgsmessagelog.h"
#include "qgspoint.h"
#include "qgsrectangle.h"

#include "qgsmaplayerregistry.h"
#include "qgsvectorlayer.h"
#include "qgsproject.h"
#include "qgsmessagelog.h"
#include "qgsgeometryvalidator.h"

#ifndef Q_WS_WIN
#include <netinet/in.h>
#else
#include <winsock.h>
#endif

#define DEFAULT_QUADRANT_SEGMENTS 8

#define CATCH_GEOS(r) \
  catch (GEOSException &e) \
  { \
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr("GEOS") ); \
    return r; \
  }

class GEOSException
{
  public:
    GEOSException( QString theMsg )
    {
      if ( theMsg == "Unknown exception thrown"  && lastMsg.isNull() )
      {
        msg = theMsg;
      }
      else
      {
        msg = theMsg;
        lastMsg = msg;
      }
    }

    // copy constructor
    GEOSException( const GEOSException &rhs )
    {
      *this = rhs;
    }

    ~GEOSException()
    {
      if ( lastMsg == msg )
        lastMsg = QString::null;
    }

    QString what()
    {
      return msg;
    }

  private:
    QString msg;
    static QString lastMsg;
};

QString GEOSException::lastMsg;

static void throwGEOSException( const char *fmt, ... )
{
  va_list ap;
  char buffer[1024];

  va_start( ap, fmt );
  vsnprintf( buffer, sizeof buffer, fmt, ap );
  va_end( ap );

  QgsDebugMsg( QString( "GEOS exception: %1" ).arg( buffer ) );

  throw GEOSException( QString::fromUtf8( buffer ) );
}

static void printGEOSNotice( const char *fmt, ... )
{
#if defined(QGISDEBUG)
  va_list ap;
  char buffer[1024];

  va_start( ap, fmt );
  vsnprintf( buffer, sizeof buffer, fmt, ap );
  va_end( ap );

  QgsDebugMsg( QString( "GEOS notice: %1" ).arg( QString::fromUtf8( buffer ) ) );
#else
  Q_UNUSED( fmt );
#endif
}

class GEOSInit
{
  public:
    GEOSInit()
    {
      initGEOS( printGEOSNotice, throwGEOSException );
    }

    ~GEOSInit()
    {
      finishGEOS();
    }
};

static GEOSInit geosinit;


#if defined(GEOS_VERSION_MAJOR) && (GEOS_VERSION_MAJOR<3)
#define GEOSGeom_getCoordSeq(g) GEOSGeom_getCoordSeq( (GEOSGeometry *) g )
#define GEOSGetExteriorRing(g) GEOSGetExteriorRing( (GEOSGeometry *)g )
#define GEOSGetNumInteriorRings(g) GEOSGetNumInteriorRings( (GEOSGeometry *)g )
#define GEOSGetInteriorRingN(g,i) GEOSGetInteriorRingN( (GEOSGeometry *)g, i )
#define GEOSDisjoint(g0,g1) GEOSDisjoint( (GEOSGeometry *)g0, (GEOSGeometry*)g1 )
#define GEOSIntersection(g0,g1) GEOSIntersection( (GEOSGeometry*) g0, (GEOSGeometry*)g1 )
#define GEOSBuffer(g, d, s) GEOSBuffer( (GEOSGeometry*) g, d, s )
#define GEOSArea(g, a) GEOSArea( (GEOSGeometry*) g, a )
#define GEOSSimplify(g, t) GEOSSimplify( (GEOSGeometry*) g, t )
#define GEOSGetCentroid(g) GEOSGetCentroid( (GEOSGeometry*) g )

#define GEOSCoordSeq_getSize(cs,n) GEOSCoordSeq_getSize( (GEOSCoordSequence *) cs, n )
#define GEOSCoordSeq_getX(cs,i,x) GEOSCoordSeq_getX( (GEOSCoordSequence *)cs, i, x )
#define GEOSCoordSeq_getY(cs,i,y) GEOSCoordSeq_getY( (GEOSCoordSequence *)cs, i, y )

static GEOSGeometry *createGeosCollection( int typeId, QVector<GEOSGeometry*> geoms );

static GEOSGeometry *cloneGeosGeom( const GEOSGeometry *geom )
{
  // for GEOS < 3.0 we have own cloning function
  // because when cloning multipart geometries they're copied into more general geometry collection instance
  int type = GEOSGeomTypeId(( GEOSGeometry * ) geom );

  if ( type == GEOS_MULTIPOINT || type == GEOS_MULTILINESTRING || type == GEOS_MULTIPOLYGON )
  {
    QVector<GEOSGeometry *> geoms;

    try
    {

      for ( int i = 0; i < GEOSGetNumGeometries(( GEOSGeometry * )geom ); ++i )
        geoms << GEOSGeom_clone(( GEOSGeometry * ) GEOSGetGeometryN(( GEOSGeometry * ) geom, i ) );

      return createGeosCollection( type, geoms );
    }
    catch ( GEOSException &e )
    {
      QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
      for ( int i = 0; i < geoms.count(); i++ )
        GEOSGeom_destroy( geoms[i] );

      return 0;
    }
  }
  else
  {
    return GEOSGeom_clone(( GEOSGeometry * ) geom );
  }
}

#define GEOSGeom_clone(g) cloneGeosGeom(g)
#endif

QgsGeometry::QgsGeometry()
    : mGeometry( 0 )
    , mGeometrySize( 0 )
    , mGeos( 0 )
    , mDirtyWkb( false )
    , mDirtyGeos( false )
{
}

QgsGeometry::QgsGeometry( QgsGeometry const & rhs )
    : mGeometry( 0 )
    , mGeometrySize( rhs.mGeometrySize )
    , mDirtyWkb( rhs.mDirtyWkb )
    , mDirtyGeos( rhs.mDirtyGeos )
{
  if ( mGeometrySize && rhs.mGeometry )
  {
    mGeometry = new unsigned char[mGeometrySize];
    memcpy( mGeometry, rhs.mGeometry, mGeometrySize );
  }

  // deep-copy the GEOS Geometry if appropriate
  if ( rhs.mGeos )
  {
    mGeos = GEOSGeom_clone( rhs.mGeos );
  }
  else
  {
    mGeos = 0;
  }
}

QgsGeometry::~QgsGeometry()
{
  if ( mGeometry )
  {
    delete [] mGeometry;
  }

  if ( mGeos )
  {
    GEOSGeom_destroy( mGeos );
  }
}

static unsigned int getNumGeosPoints( const GEOSGeometry *geom )
{
  unsigned int n;
  const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( geom );
  GEOSCoordSeq_getSize( cs, &n );
  return n;
}

static GEOSGeometry *createGeosPoint( const QgsPoint &point )
{
  GEOSCoordSequence *coord = GEOSCoordSeq_create( 1, 2 );
  GEOSCoordSeq_setX( coord, 0, point.x() );
  GEOSCoordSeq_setY( coord, 0, point.y() );
  return GEOSGeom_createPoint( coord );
}

static GEOSCoordSequence *createGeosCoordSequence( const QgsPolyline& points )
{
  GEOSCoordSequence *coord = 0;

  try
  {
    coord = GEOSCoordSeq_create( points.count(), 2 );
    int i;
    for ( i = 0; i < points.count(); i++ )
    {
      GEOSCoordSeq_setX( coord, i, points[i].x() );
      GEOSCoordSeq_setY( coord, i, points[i].y() );
    }
    return coord;
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    /*if ( coord )
      GEOSCoordSeq_destroy( coord );*/
    throw;
  }
}

static GEOSGeometry *createGeosCollection( int typeId, QVector<GEOSGeometry*> geoms )
{
  GEOSGeometry **geomarr = new GEOSGeometry*[ geoms.size()];
  if ( !geomarr )
    return 0;

  for ( int i = 0; i < geoms.size(); i++ )
    geomarr[i] = geoms[i];

  GEOSGeometry *geom = 0;

  try
  {
    geom = GEOSGeom_createCollection( typeId, geomarr, geoms.size() );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
  }

  delete [] geomarr;

  return geom;
}

static GEOSGeometry *createGeosLineString( const QgsPolyline& polyline )
{
  GEOSCoordSequence *coord = 0;

  try
  {
    coord = createGeosCoordSequence( polyline );
    return GEOSGeom_createLineString( coord );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    //MH: for strange reasons, geos3 crashes when removing the coordinate sequence
    //if ( coord )
    //GEOSCoordSeq_destroy( coord );
    return 0;
  }
}

static GEOSGeometry *createGeosLinearRing( const QgsPolyline& polyline )
{
  GEOSCoordSequence *coord = 0;

  if ( polyline.count() == 0 )
    return 0;

  try
  {
    if ( polyline[0] != polyline[polyline.size()-1] )
    {
      // Ring not closed
      QgsPolyline closed( polyline );
      closed << closed[0];
      coord = createGeosCoordSequence( closed );
    }
    else
    {
      coord = createGeosCoordSequence( polyline );
    }

    return GEOSGeom_createLinearRing( coord );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    /* as MH has noticed ^, this crashes geos
    if ( coord )
      GEOSCoordSeq_destroy( coord );*/
    return 0;
  }
}

static GEOSGeometry *createGeosPolygon( const QVector<GEOSGeometry*> &rings )
{
  GEOSGeometry *shell = rings[0];
  GEOSGeometry **holes = NULL;

  if ( rings.size() > 1 )
  {
    holes = new GEOSGeometry*[ rings.size()-1 ];
    if ( !holes )
      return 0;

    for ( int i = 0; i < rings.size() - 1; i++ )
      holes[i] = rings[i+1];
  }

  GEOSGeometry *geom = GEOSGeom_createPolygon( shell, holes, rings.size() - 1 );

  if ( holes )
    delete [] holes;

  return geom;
}

static GEOSGeometry *createGeosPolygon( GEOSGeometry *shell )
{
  return createGeosPolygon( QVector<GEOSGeometry*>() << shell );
}

static GEOSGeometry *createGeosPolygon( const QgsPolygon& polygon )
{
  if ( polygon.count() == 0 )
    return 0;

  QVector<GEOSGeometry *> geoms;

  try
  {
    for ( int i = 0; i < polygon.count(); i++ )
      geoms << createGeosLinearRing( polygon[i] );

    return createGeosPolygon( geoms );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    for ( int i = 0; i < geoms.count(); i++ )
      GEOSGeom_destroy( geoms[i] );
    return 0;
  }
}

static QgsGeometry *fromGeosGeom( GEOSGeometry *geom )
{
  if ( !geom )
    return 0;

  QgsGeometry* g = new QgsGeometry;
  g->fromGeos( geom );
  return g;
}

QgsGeometry* QgsGeometry::fromWkt( QString wkt )
{
  try
  {
#if defined(GEOS_VERSION_MAJOR) && (GEOS_VERSION_MAJOR>=3)
    GEOSWKTReader *reader = GEOSWKTReader_create();
    QgsGeometry *g = fromGeosGeom( GEOSWKTReader_read( reader, wkt.toLocal8Bit().data() ) );
    GEOSWKTReader_destroy( reader );
    return g;
#else
    return fromGeosGeom( GEOSGeomFromWKT( wkt.toLocal8Bit().data() ) );
#endif
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    return 0;
  }
}

QgsGeometry* QgsGeometry::fromPoint( const QgsPoint& point )
{
  return fromGeosGeom( createGeosPoint( point ) );
}

QgsGeometry* QgsGeometry::fromPolyline( const QgsPolyline& polyline )
{
  return fromGeosGeom( createGeosLineString( polyline ) );
}

QgsGeometry* QgsGeometry::fromPolygon( const QgsPolygon& polygon )
{
  return fromGeosGeom( createGeosPolygon( polygon ) );
}

QgsGeometry* QgsGeometry::fromMultiPoint( const QgsMultiPoint& multipoint )
{
  QVector<GEOSGeometry *> geoms;

  try
  {
    for ( int i = 0; i < multipoint.size(); ++i )
    {
      geoms << createGeosPoint( multipoint[i] );
    }

    return fromGeosGeom( createGeosCollection( GEOS_MULTIPOINT, geoms ) );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

    for ( int i = 0; i < geoms.size(); ++i )
      GEOSGeom_destroy( geoms[i] );

    return 0;
  }
}

QgsGeometry* QgsGeometry::fromMultiPolyline( const QgsMultiPolyline& multiline )
{
  QVector<GEOSGeometry *> geoms;

  try
  {
    for ( int i = 0; i < multiline.count(); i++ )
      geoms << createGeosLineString( multiline[i] );

    return fromGeosGeom( createGeosCollection( GEOS_MULTILINESTRING, geoms ) );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

    for ( int i = 0; i < geoms.count(); i++ )
      GEOSGeom_destroy( geoms[i] );

    return 0;
  }
}

QgsGeometry* QgsGeometry::fromMultiPolygon( const QgsMultiPolygon& multipoly )
{
  if ( multipoly.count() == 0 )
    return 0;

  QVector<GEOSGeometry *> geoms;

  try
  {
    for ( int i = 0; i < multipoly.count(); i++ )
      geoms << createGeosPolygon( multipoly[i] );

    return fromGeosGeom( createGeosCollection( GEOS_MULTIPOLYGON, geoms ) );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

    for ( int i = 0; i < geoms.count(); i++ )
      GEOSGeom_destroy( geoms[i] );

    return 0;
  }
}

QgsGeometry* QgsGeometry::fromRect( const QgsRectangle& rect )
{
  QgsPolyline ring;
  ring.append( QgsPoint( rect.xMinimum(), rect.yMinimum() ) );
  ring.append( QgsPoint( rect.xMaximum(), rect.yMinimum() ) );
  ring.append( QgsPoint( rect.xMaximum(), rect.yMaximum() ) );
  ring.append( QgsPoint( rect.xMinimum(), rect.yMaximum() ) );
  ring.append( QgsPoint( rect.xMinimum(), rect.yMinimum() ) );

  QgsPolygon polygon;
  polygon.append( ring );

  return fromPolygon( polygon );
}


QgsGeometry & QgsGeometry::operator=( QgsGeometry const & rhs )
{
  if ( &rhs == this )
  {
    return *this;
  }

  // remove old geometry if it exists
  if ( mGeometry )
  {
    delete [] mGeometry;
    mGeometry = 0;
  }

  mGeometrySize    = rhs.mGeometrySize;

  // deep-copy the GEOS Geometry if appropriate
  GEOSGeom_destroy( mGeos );
  mGeos = rhs.mGeos ? GEOSGeom_clone( rhs.mGeos ) : 0;

  mDirtyGeos = rhs.mDirtyGeos;
  mDirtyWkb  = rhs.mDirtyWkb;

  if ( mGeometrySize && rhs.mGeometry )
  {
    mGeometry = new unsigned char[mGeometrySize];
    memcpy( mGeometry, rhs.mGeometry, mGeometrySize );
  }

  return *this;
} // QgsGeometry::operator=( QgsGeometry const & rhs )


void QgsGeometry::fromWkb( unsigned char * wkb, size_t length )
{
  // delete any existing WKB geometry before assigning new one
  if ( mGeometry )
  {
    delete [] mGeometry;
    mGeometry = 0;
  }
  if ( mGeos )
  {
    GEOSGeom_destroy( mGeos );
    mGeos = 0;
  }

  mGeometry = wkb;
  mGeometrySize = length;

  mDirtyWkb   = false;
  mDirtyGeos  = true;
}

unsigned char * QgsGeometry::asWkb()
{
  if ( mDirtyWkb )
  {
    // convert from GEOS
    exportGeosToWkb();
  }

  return mGeometry;
}

size_t QgsGeometry::wkbSize()
{
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  return mGeometrySize;
}

GEOSGeometry* QgsGeometry::asGeos()
{
  if ( mDirtyGeos )
  {
    if ( !exportWkbToGeos() )
    {
      return 0;
    }
  }
  return mGeos;
}


QGis::WkbType QgsGeometry::wkbType()
{
  unsigned char *geom = asWkb(); // ensure that wkb representation exists
  if ( geom && wkbSize() >= 5 )
  {
    unsigned int wkbType;
    memcpy( &wkbType, ( geom + 1 ), sizeof( wkbType ) );
    return ( QGis::WkbType ) wkbType;
  }
  else
  {
    return QGis::WKBUnknown;
  }
}


QGis::GeometryType QgsGeometry::type()
{
  if ( mDirtyWkb )
  {
    // convert from GEOS
    exportGeosToWkb();
  }

  switch ( wkbType() )
  {
    case QGis::WKBPoint:
    case QGis::WKBPoint25D:
    case QGis::WKBMultiPoint:
    case QGis::WKBMultiPoint25D:
      return QGis::Point;

    case QGis::WKBLineString:
    case QGis::WKBLineString25D:
    case QGis::WKBMultiLineString:
    case QGis::WKBMultiLineString25D:
      return QGis::Line;

    case QGis::WKBPolygon:
    case QGis::WKBPolygon25D:
    case QGis::WKBMultiPolygon:
    case QGis::WKBMultiPolygon25D:
      return QGis::Polygon;

    default:
      return QGis::UnknownGeometry;
  }
}

bool QgsGeometry::isMultipart()
{
  if ( mDirtyWkb )
  {
    // convert from GEOS
    exportGeosToWkb();
  }

  QGis::WkbType type = wkbType();
  if ( type == QGis::WKBMultiPoint ||
       type == QGis::WKBMultiPoint25D ||
       type == QGis::WKBMultiLineString ||
       type == QGis::WKBMultiLineString25D ||
       type == QGis::WKBMultiPolygon ||
       type == QGis::WKBMultiPolygon25D )
    return true;

  return false;
}


void QgsGeometry::fromGeos( GEOSGeometry* geos )
{
  // TODO - make this more heap-friendly

  if ( mGeos )
  {
    GEOSGeom_destroy( mGeos );
    mGeos = 0;
  }
  if ( mGeometry )
  {
    delete [] mGeometry;
    mGeometry = 0;
  }

  mGeos = geos;

  mDirtyWkb   = true;
  mDirtyGeos  = false;
}

QgsPoint QgsGeometry::closestVertex( const QgsPoint& point, int& atVertex, int& beforeVertex, int& afterVertex, double& sqrDist )
{
  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return QgsPoint( 0, 0 );
  }

  int vertexnr = -1;
  int vertexcounter = 0;
  QGis::WkbType wkbType;
  double actdist = std::numeric_limits<double>::max();
  double x = 0;
  double y = 0;
  double *tempx, *tempy;
  memcpy( &wkbType, ( mGeometry + 1 ), sizeof( int ) );
  beforeVertex = -1;
  afterVertex = -1;
  bool hasZValue = false;

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      x = *(( double * )( mGeometry + 5 ) );
      y = *(( double * )( mGeometry + 5 + sizeof( double ) ) );
      actdist = point.sqrDist( x, y );
      vertexnr = 0;
      break;
    }
    case QGis::WKBLineString25D:
      hasZValue = true;

      // fall-through

    case QGis::WKBLineString:
    {
      unsigned char* ptr = mGeometry + 5;
      int* npoints = ( int* )ptr;
      ptr += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        tempx = ( double* )ptr;
        ptr += sizeof( double );
        tempy = ( double* )ptr;
        if ( point.sqrDist( *tempx, *tempy ) < actdist )
        {
          x = *tempx;
          y = *tempy;
          actdist = point.sqrDist( *tempx, *tempy );
          vertexnr = index;
          if ( index == 0 )//assign the rubber band indices
          {
            beforeVertex = -1;
          }
          else
          {
            beforeVertex = index - 1;
          }
          if ( index == ( *npoints - 1 ) )
          {
            afterVertex = -1;
          }
          else
          {
            afterVertex = index + 1;
          }
        }
        ptr += sizeof( double );
        if ( hasZValue ) //skip z-coordinate for 25D geometries
        {
          ptr += sizeof( double );
        }
      }
      break;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nrings = ( int* )( mGeometry + 5 );
      int* npoints;
      unsigned char* ptr = mGeometry + 9;
      for ( int index = 0; index < *nrings; ++index )
      {
        npoints = ( int* )ptr;
        ptr += sizeof( int );
        for ( int index2 = 0; index2 < *npoints; ++index2 )
        {
          tempx = ( double* )ptr;
          ptr += sizeof( double );
          tempy = ( double* )ptr;
          if ( point.sqrDist( *tempx, *tempy ) < actdist )
          {
            x = *tempx;
            y = *tempy;
            actdist = point.sqrDist( *tempx, *tempy );
            vertexnr = vertexcounter;
            //assign the rubber band indices
            if ( index2 == 0 )
            {
              beforeVertex = vertexcounter + ( *npoints - 2 );
              afterVertex = vertexcounter + 1;
            }
            else if ( index2 == ( *npoints - 1 ) )
            {
              beforeVertex = vertexcounter - 1;
              afterVertex = vertexcounter - ( *npoints - 2 );
            }
            else
            {
              beforeVertex = vertexcounter - 1;
              afterVertex = vertexcounter + 1;
            }
          }
          ptr += sizeof( double );
          if ( hasZValue ) //skip z-coordinate for 25D geometries
          {
            ptr += sizeof( double );
          }
          ++vertexcounter;
        }
      }
      break;
    }
    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      unsigned char* ptr = mGeometry + 5;
      int* npoints = ( int* )ptr;
      ptr += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        ptr += ( 1 + sizeof( int ) ); //skip endian and point type
        tempx = ( double* )ptr;
        tempy = ( double* )( ptr + sizeof( double ) );
        if ( point.sqrDist( *tempx, *tempy ) < actdist )
        {
          x = *tempx;
          y = *tempy;
          actdist = point.sqrDist( *tempx, *tempy );
          vertexnr = index;
        }
        ptr += ( 2 * sizeof( double ) );
        if ( hasZValue ) //skip z-coordinate for 25D geometries
        {
          ptr += sizeof( double );
        }
      }
      break;
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      unsigned char* ptr = mGeometry + 5;
      int* nlines = ( int* )ptr;
      int* npoints = 0;
      ptr += sizeof( int );
      for ( int index = 0; index < *nlines; ++index )
      {
        ptr += ( sizeof( int ) + 1 );
        npoints = ( int* )ptr;
        ptr += sizeof( int );
        for ( int index2 = 0; index2 < *npoints; ++index2 )
        {
          tempx = ( double* )ptr;
          ptr += sizeof( double );
          tempy = ( double* )ptr;
          ptr += sizeof( double );
          if ( point.sqrDist( *tempx, *tempy ) < actdist )
          {
            x = *tempx;
            y = *tempy;
            actdist = point.sqrDist( *tempx, *tempy );
            vertexnr = vertexcounter;

            if ( index2 == 0 )//assign the rubber band indices
            {
              beforeVertex = -1;
            }
            else
            {
              beforeVertex = vertexnr - 1;
            }
            if ( index2 == ( *npoints ) - 1 )
            {
              afterVertex = -1;
            }
            else
            {
              afterVertex = vertexnr + 1;
            }
          }
          if ( hasZValue ) //skip z-coordinate for 25D geometries
          {
            ptr += sizeof( double );
          }
          ++vertexcounter;
        }
      }
      break;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      unsigned char* ptr = mGeometry + 5;
      int* npolys = ( int* )ptr;
      int* nrings;
      int* npoints;
      ptr += sizeof( int );
      for ( int index = 0; index < *npolys; ++index )
      {
        ptr += ( 1 + sizeof( int ) ); //skip endian and polygon type
        nrings = ( int* )ptr;
        ptr += sizeof( int );
        for ( int index2 = 0; index2 < *nrings; ++index2 )
        {
          npoints = ( int* )ptr;
          ptr += sizeof( int );
          for ( int index3 = 0; index3 < *npoints; ++index3 )
          {
            tempx = ( double* )ptr;
            ptr += sizeof( double );
            tempy = ( double* )ptr;
            if ( point.sqrDist( *tempx, *tempy ) < actdist )
            {
              x = *tempx;
              y = *tempy;
              actdist = point.sqrDist( *tempx, *tempy );
              vertexnr = vertexcounter;

              //assign the rubber band indices
              if ( index3 == 0 )
              {
                beforeVertex = vertexcounter + ( *npoints - 2 );
                afterVertex = vertexcounter + 1;
              }
              else if ( index3 == ( *npoints - 1 ) )
              {
                beforeVertex = vertexcounter - 1;
                afterVertex = vertexcounter - ( *npoints - 2 );
              }
              else
              {
                beforeVertex = vertexcounter - 1;
                afterVertex = vertexcounter + 1;
              }
            }
            ptr += sizeof( double );
            if ( hasZValue ) //skip z-coordinate for 25D geometries
            {
              ptr += sizeof( double );
            }
            ++vertexcounter;
          }
        }
      }
      break;
    }
    default:
      break;
  }
  sqrDist = actdist;
  atVertex = vertexnr;
  return QgsPoint( x, y );
}


void QgsGeometry::adjacentVertices( int atVertex, int& beforeVertex, int& afterVertex )
{
  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  beforeVertex = -1;
  afterVertex = -1;

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return;
  }

  int vertexcounter = 0;

  QGis::WkbType wkbType;
  bool hasZValue = false;

  memcpy( &wkbType, ( mGeometry + 1 ), sizeof( int ) );

  switch ( wkbType )
  {
    case QGis::WKBPoint:
    {
      // NOOP - Points do not have adjacent verticies
      break;
    }
    case QGis::WKBLineString25D:
    case QGis::WKBLineString:
    {
      unsigned char* ptr = mGeometry + 5;
      int* npoints = ( int* ) ptr;

      const int index = atVertex;

      // assign the rubber band indices

      if ( index == 0 )
      {
        beforeVertex = -1;
      }
      else
      {
        beforeVertex = index - 1;
      }

      if ( index == ( *npoints - 1 ) )
      {
        afterVertex = -1;
      }
      else
      {
        afterVertex = index + 1;
      }

      break;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nrings = ( int* )( mGeometry + 5 );
      int* npoints;
      unsigned char* ptr = mGeometry + 9;

      // Walk through the POLYGON WKB

      for ( int index0 = 0; index0 < *nrings; ++index0 )
      {
        npoints = ( int* )ptr;
        ptr += sizeof( int );

        for ( int index1 = 0; index1 < *npoints; ++index1 )
        {
          ptr += sizeof( double );
          ptr += sizeof( double );
          if ( hasZValue ) //skip z-coordinate for 25D geometries
          {
            ptr += sizeof( double );
          }
          if ( vertexcounter == atVertex )
          {
            if ( index1 == 0 )
            {
              beforeVertex = vertexcounter + ( *npoints - 2 );
              afterVertex = vertexcounter + 1;
            }
            else if ( index1 == ( *npoints - 1 ) )
            {
              beforeVertex = vertexcounter - 1;
              afterVertex = vertexcounter - ( *npoints - 2 );
            }
            else
            {
              beforeVertex = vertexcounter - 1;
              afterVertex = vertexcounter + 1;
            }
          }

          ++vertexcounter;
        }
      }
      break;
    }
    case QGis::WKBMultiPoint25D:
    case QGis::WKBMultiPoint:
    {
      // NOOP - Points do not have adjacent verticies
      break;
    }

    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      unsigned char* ptr = mGeometry + 5;
      int* nlines = ( int* )ptr;
      int* npoints = 0;
      ptr += sizeof( int );

      for ( int index0 = 0; index0 < *nlines; ++index0 )
      {
        ptr += ( sizeof( int ) + 1 );
        npoints = ( int* )ptr;
        ptr += sizeof( int );

        for ( int index1 = 0; index1 < *npoints; ++index1 )
        {
          ptr += sizeof( double );
          ptr += sizeof( double );
          if ( hasZValue ) //skip z-coordinate for 25D geometries
          {
            ptr += sizeof( double );
          }

          if ( vertexcounter == atVertex )
          {
            // Found the vertex of the linestring we were looking for.
            if ( index1 == 0 )
            {
              beforeVertex = -1;
            }
            else
            {
              beforeVertex = vertexcounter - 1;
            }
            if ( index1 == ( *npoints ) - 1 )
            {
              afterVertex = -1;
            }
            else
            {
              afterVertex = vertexcounter + 1;
            }
          }
          ++vertexcounter;
        }
      }
      break;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      unsigned char* ptr = mGeometry + 5;
      int* npolys = ( int* )ptr;
      int* nrings;
      int* npoints;
      ptr += sizeof( int );

      for ( int index0 = 0; index0 < *npolys; ++index0 )
      {
        ptr += ( 1 + sizeof( int ) ); //skip endian and polygon type
        nrings = ( int* )ptr;
        ptr += sizeof( int );

        for ( int index1 = 0; index1 < *nrings; ++index1 )
        {
          npoints = ( int* )ptr;
          ptr += sizeof( int );

          for ( int index2 = 0; index2 < *npoints; ++index2 )
          {
            ptr += sizeof( double );
            ptr += sizeof( double );
            if ( hasZValue ) //skip z-coordinate for 25D geometries
            {
              ptr += sizeof( double );
            }
            if ( vertexcounter == atVertex )
            {
              // Found the vertex of the linear-ring of the polygon we were looking for.
              // assign the rubber band indices

              if ( index2 == 0 )
              {
                beforeVertex = vertexcounter + ( *npoints - 2 );
                afterVertex = vertexcounter + 1;
              }
              else if ( index2 == ( *npoints - 1 ) )
              {
                beforeVertex = vertexcounter - 1;
                afterVertex = vertexcounter - ( *npoints - 2 );
              }
              else
              {
                beforeVertex = vertexcounter - 1;
                afterVertex = vertexcounter + 1;
              }
            }
            ++vertexcounter;
          }
        }
      }

      break;
    }

    default:
      break;
  } // switch (wkbType)
}



bool QgsGeometry::insertVertex( double x, double y,
                                int beforeVertex,
                                const GEOSCoordSequence*  old_sequence,
                                GEOSCoordSequence** new_sequence )

{
  // Bounds checking
  if ( beforeVertex < 0 )
  {
    *new_sequence = 0;
    return false;
  }

  unsigned int numPoints;
  GEOSCoordSeq_getSize( old_sequence, &numPoints );

  *new_sequence = GEOSCoordSeq_create( numPoints + 1, 2 );
  if ( !*new_sequence )
    return false;

  bool inserted = false;
  for ( unsigned int i = 0, j = 0; i < numPoints; i++, j++ )
  {
    // Do we insert the new vertex here?
    if ( beforeVertex == static_cast<int>( i ) )
    {
      GEOSCoordSeq_setX( *new_sequence, j, x );
      GEOSCoordSeq_setY( *new_sequence, j, y );
      j++;
      inserted = true;
    }

    double aX, aY;
    GEOSCoordSeq_getX( old_sequence, i, &aX );
    GEOSCoordSeq_getY( old_sequence, i, &aY );

    GEOSCoordSeq_setX( *new_sequence, j, aX );
    GEOSCoordSeq_setY( *new_sequence, j, aY );
  }

  if ( !inserted )
  {
    // The beforeVertex is greater than the actual number of vertices
    // in the geometry - append it.
    GEOSCoordSeq_setX( *new_sequence, numPoints, x );
    GEOSCoordSeq_setY( *new_sequence, numPoints, y );
  }
  // TODO: Check that the sequence is still simple, e.g. with GEOS_GEOM::Geometry->isSimple()

  return inserted;
}

bool QgsGeometry::moveVertex( double x, double y, int atVertex )
{
  int vertexnr = atVertex;

  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return false;
  }

  QGis::WkbType wkbType;
  bool hasZValue = false;
  unsigned char* ptr = mGeometry + 1;
  memcpy( &wkbType, ptr, sizeof( wkbType ) );
  ptr += sizeof( wkbType );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      if ( vertexnr == 0 )
      {
        memcpy( ptr, &x, sizeof( double ) );
        ptr += sizeof( double );
        memcpy( ptr, &y, sizeof( double ) );
        mDirtyGeos = true;
        return true;
      }
      else
      {
        return false;
      }
    }
    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      int* nrPoints = ( int* )ptr;
      if ( vertexnr > *nrPoints || vertexnr < 0 )
      {
        return false;
      }
      ptr += sizeof( int );
      if ( hasZValue )
      {
        ptr += ( 3 * sizeof( double ) + 1 + sizeof( int ) ) * vertexnr;
      }
      else
      {
        ptr += ( 2 * sizeof( double ) + 1 + sizeof( int ) ) * vertexnr;
      }
      ptr += ( 1 + sizeof( int ) );
      memcpy( ptr, &x, sizeof( double ) );
      ptr += sizeof( double );
      memcpy( ptr, &y, sizeof( double ) );
      mDirtyGeos = true;
      return true;
    }
    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      int* nrPoints = ( int* )ptr;
      if ( vertexnr > *nrPoints || vertexnr < 0 )
      {
        return false;
      }
      ptr += sizeof( int );
      ptr += 2 * sizeof( double ) * vertexnr;
      if ( hasZValue )
      {
        ptr += sizeof( double ) * vertexnr;
      }
      memcpy( ptr, &x, sizeof( double ) );
      ptr += sizeof( double );
      memcpy( ptr, &y, sizeof( double ) );
      mDirtyGeos = true;
      return true;
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      int* nrLines = ( int* )ptr;
      ptr += sizeof( int );
      int* nrPoints = 0; //numer of points in a line
      int pointindex = 0;
      for ( int linenr = 0; linenr < *nrLines; ++linenr )
      {
        ptr += sizeof( int ) + 1;
        nrPoints = ( int* )ptr;
        ptr += sizeof( int );
        if ( vertexnr >= pointindex && vertexnr < pointindex + ( *nrPoints ) )
        {
          ptr += ( vertexnr - pointindex ) * 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += ( vertexnr - pointindex ) * sizeof( double );
          }
          memcpy( ptr, &x, sizeof( double ) );
          memcpy( ptr + sizeof( double ), &y, sizeof( double ) );
          mDirtyGeos = true;
          return true;
        }
        pointindex += ( *nrPoints );
        ptr += 2 * sizeof( double ) * ( *nrPoints );
        if ( hasZValue )
        {
          ptr += sizeof( double ) * ( *nrPoints );
        }
      }
      return false;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nrRings = ( int* )ptr;
      ptr += sizeof( int );
      int* nrPoints = 0; //numer of points in a ring
      int pointindex = 0;

      for ( int ringnr = 0; ringnr < *nrRings; ++ringnr )
      {
        nrPoints = ( int* )ptr;
        ptr += sizeof( int );
        if ( vertexnr == pointindex || vertexnr == pointindex + ( *nrPoints - 1 ) )//move two points
        {
          memcpy( ptr, &x, sizeof( double ) );
          memcpy( ptr + sizeof( double ), &y, sizeof( double ) );
          if ( hasZValue )
          {
            memcpy( ptr + 3*sizeof( double )*( *nrPoints - 1 ), &x, sizeof( double ) );
          }
          else
          {
            memcpy( ptr + 2*sizeof( double )*( *nrPoints - 1 ), &x, sizeof( double ) );
          }
          if ( hasZValue )
          {
            memcpy( ptr + sizeof( double ) + 3*sizeof( double )*( *nrPoints - 1 ), &y, sizeof( double ) );
          }
          else
          {
            memcpy( ptr + sizeof( double ) + 2*sizeof( double )*( *nrPoints - 1 ), &y, sizeof( double ) );
          }
          mDirtyGeos = true;
          return true;
        }
        else if ( vertexnr > pointindex && vertexnr < pointindex + ( *nrPoints - 1 ) )//move only one point
        {
          ptr += 2 * sizeof( double ) * ( vertexnr - pointindex );
          if ( hasZValue )
          {
            ptr += sizeof( double ) * ( vertexnr - pointindex );
          }
          memcpy( ptr, &x, sizeof( double ) );
          ptr += sizeof( double );
          memcpy( ptr, &y, sizeof( double ) );
          mDirtyGeos = true;
          return true;
        }
        ptr += 2 * sizeof( double ) * ( *nrPoints );
        if ( hasZValue )
        {
          ptr += sizeof( double ) * ( *nrPoints );
        }
        pointindex += *nrPoints;
      }
      return false;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      int* nrPolygons = ( int* )ptr;
      ptr += sizeof( int );
      int* nrRings = 0; //number of rings in a polygon
      int* nrPoints = 0; //number of points in a ring
      int pointindex = 0;

      for ( int polynr = 0; polynr < *nrPolygons; ++polynr )
      {
        ptr += ( 1 + sizeof( int ) ); //skip endian and polygon type
        nrRings = ( int* )ptr;
        ptr += sizeof( int );
        for ( int ringnr = 0; ringnr < *nrRings; ++ringnr )
        {
          nrPoints = ( int* )ptr;
          ptr += sizeof( int );
          if ( vertexnr == pointindex || vertexnr == pointindex + ( *nrPoints - 1 ) )//move two points
          {
            memcpy( ptr, &x, sizeof( double ) );
            memcpy( ptr + sizeof( double ), &y, sizeof( double ) );
            if ( hasZValue )
            {
              memcpy( ptr + 3*sizeof( double )*( *nrPoints - 1 ), &x, sizeof( double ) );
            }
            else
            {
              memcpy( ptr + 2*sizeof( double )*( *nrPoints - 1 ), &x, sizeof( double ) );
            }
            if ( hasZValue )
            {
              memcpy( ptr + sizeof( double ) + 3*sizeof( double )*( *nrPoints - 1 ), &y, sizeof( double ) );
            }
            else
            {
              memcpy( ptr + sizeof( double ) + 2*sizeof( double )*( *nrPoints - 1 ), &y, sizeof( double ) );
            }
            mDirtyGeos = true;
            return true;
          }
          else if ( vertexnr > pointindex && vertexnr < pointindex + ( *nrPoints - 1 ) )//move only one point
          {
            ptr += 2 * sizeof( double ) * ( vertexnr - pointindex );
            if ( hasZValue )
            {
              ptr += sizeof( double ) * ( vertexnr - pointindex );
            }
            memcpy( ptr, &x, sizeof( double ) );
            ptr += sizeof( double );
            memcpy( ptr, &y, sizeof( double ) );
            mDirtyGeos = true;
            return true;
          }
          ptr += 2 * sizeof( double ) * ( *nrPoints );
          if ( hasZValue )
          {
            ptr += sizeof( double ) * ( *nrPoints );
          }
          pointindex += *nrPoints;
        }
      }
      return false;
    }

    default:
      return false;
  }
}

bool QgsGeometry::deleteVertex( int atVertex )
{
  int vertexnr = atVertex;
  bool success = false;

  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return false;
  }

  //create a new geometry buffer for the modified geometry
  unsigned char* newbuffer;
  int pointindex = 0;
  QGis::WkbType wkbType;
  bool hasZValue = false;
  unsigned char* ptr = mGeometry + 1;
  memcpy( &wkbType, ptr, sizeof( wkbType ) );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBLineString25D:
    case QGis::WKBPolygon25D:
    case QGis::WKBMultiPoint25D:
    case QGis::WKBMultiLineString25D:
    case QGis::WKBMultiPolygon25D:
      newbuffer = new unsigned char[mGeometrySize-3*sizeof( double )];
      break;
    default:
      newbuffer = new unsigned char[mGeometrySize-2*sizeof( double )];
  }

  memcpy( newbuffer, mGeometry, 1 + sizeof( int ) ); //endian and type are the same

  ptr += sizeof( wkbType );
  unsigned char* newBufferPtr = newbuffer + 1 + sizeof( int );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      break; //cannot remove the only point vertex
    }
    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      //todo
      break;
    }
    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      int* nPoints = ( int* )ptr;
      if (( *nPoints ) < 3 || vertexnr > ( *nPoints ) - 1 || vertexnr < 0 ) //line needs at least 2 vertices
      {
        delete newbuffer;
        return false;
      }
      int newNPoints = ( *nPoints ) - 1; //new number of points
      memcpy( newBufferPtr, &newNPoints, sizeof( int ) );
      ptr += sizeof( int );
      newBufferPtr += sizeof( int );
      for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
      {
        if ( vertexnr != pointindex )
        {
          memcpy( newBufferPtr, ptr, sizeof( double ) );
          memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );
          newBufferPtr += 2 * sizeof( double );
          if ( hasZValue )
          {
            newBufferPtr += sizeof( double );
          }
        }
        else
        {
          success = true;
        }
        ptr += 2 * sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
        ++pointindex;
      }
      break;
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      int* nLines = ( int* )ptr;
      memcpy( newBufferPtr, nLines, sizeof( int ) );
      newBufferPtr += sizeof( int );
      ptr += sizeof( int );
      int* nPoints = 0; //number of points in a line
      int pointindex = 0;
      for ( int linenr = 0; linenr < *nLines; ++linenr )
      {
        memcpy( newBufferPtr, ptr, sizeof( int ) + 1 );
        ptr += ( sizeof( int ) + 1 );
        newBufferPtr += ( sizeof( int ) + 1 );
        nPoints = ( int* )ptr;
        ptr += sizeof( int );
        int newNPoint;

        //find out if the vertex is in this line
        if ( vertexnr >= pointindex && vertexnr < pointindex + ( *nPoints ) )
        {
          if ( *nPoints < 3 ) //line needs at least 2 vertices
          {
            delete newbuffer;
            return false;
          }
          newNPoint = ( *nPoints ) - 1;
        }
        else
        {
          newNPoint = *nPoints;
        }
        memcpy( newBufferPtr, &newNPoint, sizeof( int ) );
        newBufferPtr += sizeof( int );

        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          if ( vertexnr != pointindex )
          {
            memcpy( newBufferPtr, ptr, sizeof( double ) );//x
            memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//y
            newBufferPtr += 2 * sizeof( double );
            if ( hasZValue )
            {
              newBufferPtr += sizeof( double );
            }
          }
          else
          {
            success = true;
          }
          ptr += 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          ++pointindex;
        }
      }
      break;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nRings = ( int* )ptr;
      memcpy( newBufferPtr, nRings, sizeof( int ) );
      ptr += sizeof( int );
      newBufferPtr += sizeof( int );
      int* nPoints = 0; //number of points in a ring
      int pointindex = 0;

      for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
      {
        nPoints = ( int* )ptr;
        ptr += sizeof( int );
        int newNPoints;
        if ( vertexnr >= pointindex && vertexnr < pointindex + *nPoints )//vertex to delete is in this ring
        {
          if ( *nPoints < 5 ) //a ring has at least 3 points
          {
            delete newbuffer;
            return false;
          }
          newNPoints = *nPoints - 1;
        }
        else
        {
          newNPoints = *nPoints;
        }
        memcpy( newBufferPtr, &newNPoints, sizeof( int ) );
        newBufferPtr += sizeof( int );

        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          if ( vertexnr != pointindex )
          {
            memcpy( newBufferPtr, ptr, sizeof( double ) );//x
            memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//y
            newBufferPtr += 2 * sizeof( double );
            if ( hasZValue )
            {
              newBufferPtr += sizeof( double );
            }
          }
          else
          {
            if ( pointnr == 0 )//adjust the last point of the ring
            {
              memcpy( ptr + ( *nPoints - 1 )*2*sizeof( double ), ptr + 2*sizeof( double ), sizeof( double ) );
              memcpy( ptr + sizeof( double ) + ( *nPoints - 1 )*2*sizeof( double ), ptr + 3*sizeof( double ), sizeof( double ) );
            }
            if ( pointnr == ( *nPoints ) - 1 )
            {
              memcpy( newBufferPtr - ( *nPoints - 1 )*2*sizeof( double ), ptr - 2*sizeof( double ), sizeof( double ) );
              memcpy( newBufferPtr - ( *nPoints - 1 )*2*sizeof( double ) + sizeof( double ), ptr - sizeof( double ), sizeof( double ) );
            }
            success = true;
          }
          ptr += 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          ++pointindex;
        }
      }
      break;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      int* nPolys = ( int* )ptr;
      memcpy( newBufferPtr, nPolys, sizeof( int ) );
      newBufferPtr += sizeof( int );
      ptr += sizeof( int );
      int* nRings = 0;
      int* nPoints = 0;
      int pointindex = 0;

      for ( int polynr = 0; polynr < *nPolys; ++polynr )
      {
        memcpy( newBufferPtr, ptr, ( 1 + sizeof( int ) ) );
        ptr += ( 1 + sizeof( int ) ); //skip endian and polygon type
        newBufferPtr += ( 1 + sizeof( int ) );
        nRings = ( int* )ptr;
        memcpy( newBufferPtr, nRings, sizeof( int ) );
        newBufferPtr += sizeof( int );
        ptr += sizeof( int );
        for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
        {
          nPoints = ( int* )ptr;
          ptr += sizeof( int );
          int newNPoints;
          if ( vertexnr >= pointindex && vertexnr < pointindex + *nPoints )//vertex to delete is in this ring
          {
            if ( *nPoints < 5 ) //a ring has at least 3 points
            {
              delete newbuffer;
              return false;
            }
            newNPoints = *nPoints - 1;
          }
          else
          {
            newNPoints = *nPoints;
          }
          memcpy( newBufferPtr, &newNPoints, sizeof( int ) );
          newBufferPtr += sizeof( int );

          for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
          {
            if ( vertexnr != pointindex )
            {
              memcpy( newBufferPtr, ptr, sizeof( double ) );//x
              memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//y
              newBufferPtr += 2 * sizeof( double );
              if ( hasZValue )
              {
                newBufferPtr += sizeof( double );
              }
            }
            else
            {
              if ( pointnr == 0 )//adjust the last point of the ring
              {
                memcpy( ptr + ( *nPoints - 1 )*2*sizeof( double ), ptr + 2*sizeof( double ), sizeof( double ) );
                memcpy( ptr + sizeof( double ) + ( *nPoints - 1 )*2*sizeof( double ), ptr + 3*sizeof( double ), sizeof( double ) );
              }
              if ( pointnr == ( *nPoints ) - 1 )
              {
                memcpy( newBufferPtr - ( *nPoints - 1 )*2*sizeof( double ), ptr - 2*sizeof( double ), sizeof( double ) );
                memcpy( newBufferPtr - ( *nPoints - 1 )*2*sizeof( double ) + sizeof( double ), ptr - sizeof( double ), sizeof( double ) );
              }
              success = true;
            }
            ptr += 2 * sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
            ++pointindex;
          }
        }
      }
      break;
    }
    case QGis::WKBNoGeometry:
    case QGis::WKBUnknown:
      break;
  }
  if ( success )
  {
    delete [] mGeometry;
    mGeometry = newbuffer;
    mGeometrySize -= ( 2 * sizeof( double ) );
    if ( hasZValue )
    {
      mGeometrySize -= sizeof( double );
    }
    mDirtyGeos = true;
    return true;
  }
  else
  {
    delete[] newbuffer;
    return false;
  }
}

bool QgsGeometry::insertVertex( double x, double y, int beforeVertex )
{
  int vertexnr = beforeVertex;
  bool success = false;

  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return false;
  }

  //create a new geometry buffer for the modified geometry
  unsigned char* newbuffer;

  int pointindex = 0;
  QGis::WkbType wkbType;
  bool hasZValue = false;

  unsigned char* ptr = mGeometry + 1;
  memcpy( &wkbType, ptr, sizeof( wkbType ) );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBLineString25D:
    case QGis::WKBPolygon25D:
    case QGis::WKBMultiPoint25D:
    case QGis::WKBMultiLineString25D:
    case QGis::WKBMultiPolygon25D:
      newbuffer = new unsigned char[mGeometrySize+3*sizeof( double )];
      break;
    default:
      newbuffer = new unsigned char[mGeometrySize+2*sizeof( double )];
  }
  memcpy( newbuffer, mGeometry, 1 + sizeof( int ) ); //endian and type are the same

  ptr += sizeof( wkbType );
  unsigned char* newBufferPtr = newbuffer + 1 + sizeof( int );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint://cannot insert a vertex before another one on point types
    {
      delete newbuffer;
      return false;
    }
    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      //todo
      break;
    }
    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      int* nPoints = ( int* )ptr;
      if ( vertexnr > *nPoints || vertexnr < 0 )
      {
        break;
      }
      int newNPoints = ( *nPoints ) + 1;
      memcpy( newBufferPtr, &newNPoints, sizeof( int ) );
      newBufferPtr += sizeof( int );
      ptr += sizeof( int );

      for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
      {
        memcpy( newBufferPtr, ptr, sizeof( double ) );//x
        memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//x
        ptr += 2 * sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
        newBufferPtr += 2 * sizeof( double );
        if ( hasZValue )
        {
          newBufferPtr += sizeof( double );
        }
        ++pointindex;
        if ( pointindex == vertexnr )
        {
          memcpy( newBufferPtr, &x, sizeof( double ) );
          memcpy( newBufferPtr + sizeof( double ), &y, sizeof( double ) );
          newBufferPtr += 2 * sizeof( double );
          if ( hasZValue )
          {
            newBufferPtr += sizeof( double );
          }
          success = true;
        }
      }
      break;
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      int* nLines = ( int* )ptr;
      int* nPoints = 0; //number of points in a line
      ptr += sizeof( int );
      memcpy( newBufferPtr, nLines, sizeof( int ) );
      newBufferPtr += sizeof( int );
      int pointindex = 0;

      for ( int linenr = 0; linenr < *nLines; ++linenr )
      {
        memcpy( newBufferPtr, ptr, sizeof( int ) + 1 );
        ptr += ( sizeof( int ) + 1 );
        newBufferPtr += ( sizeof( int ) + 1 );
        nPoints = ( int* )ptr;
        int newNPoints;
        if ( vertexnr >= pointindex && vertexnr < ( pointindex + ( *nPoints ) ) )//point is in this ring
        {
          newNPoints = ( *nPoints ) + 1;
        }
        else
        {
          newNPoints = *nPoints;
        }
        memcpy( newBufferPtr, &newNPoints, sizeof( double ) );
        newBufferPtr += sizeof( int );
        ptr += sizeof( int );

        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          memcpy( newBufferPtr, ptr, sizeof( double ) );//x
          memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//y
          ptr += 2 * sizeof( double );
          newBufferPtr += 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
            newBufferPtr += sizeof( double );
          }
          ++pointindex;
          if ( pointindex == vertexnr )
          {
            memcpy( newBufferPtr, &x, sizeof( double ) );
            memcpy( newBufferPtr + sizeof( double ), &y, sizeof( double ) );
            newBufferPtr += 2 * sizeof( double );
            if ( hasZValue )
            {
              newBufferPtr += sizeof( double );
            }
            success = true;
          }
        }
      }
      break;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nRings = ( int* )ptr;
      int* nPoints = 0; //number of points in a ring
      ptr += sizeof( int );
      memcpy( newBufferPtr, nRings, sizeof( int ) );
      newBufferPtr += sizeof( int );
      int pointindex = 0;

      for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
      {
        nPoints = ( int* )ptr;
        int newNPoints;
        if ( vertexnr >= pointindex && vertexnr < ( pointindex + ( *nPoints ) ) )//point is in this ring
        {
          newNPoints = ( *nPoints ) + 1;
        }
        else
        {
          newNPoints = *nPoints;
        }
        memcpy( newBufferPtr, &newNPoints, sizeof( double ) );
        newBufferPtr += sizeof( int );
        ptr += sizeof( int );

        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          memcpy( newBufferPtr, ptr, sizeof( double ) );//x
          memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//y
          ptr += 2 * sizeof( double );
          newBufferPtr += 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
            newBufferPtr += sizeof( double );
          }
          ++pointindex;
          if ( pointindex == vertexnr )
          {
            memcpy( newBufferPtr, &x, sizeof( double ) );
            memcpy( newBufferPtr + sizeof( double ), &y, sizeof( double ) );
            newBufferPtr += 2 * sizeof( double );
            if ( hasZValue )
            {
              newBufferPtr += sizeof( double );
            }
            success = true;
          }
        }
      }
      break;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      int* nPolys = ( int* )ptr;
      int* nRings = 0; //number of rings in a polygon
      int* nPoints = 0; //number of points in a ring
      memcpy( newBufferPtr, nPolys, sizeof( int ) );
      ptr += sizeof( int );
      newBufferPtr += sizeof( int );
      int pointindex = 0;

      for ( int polynr = 0; polynr < *nPolys; ++polynr )
      {
        memcpy( newBufferPtr, ptr, ( 1 + sizeof( int ) ) );
        ptr += ( 1 + sizeof( int ) );//skip endian and polygon type
        newBufferPtr += ( 1 + sizeof( int ) );
        nRings = ( int* )ptr;
        ptr += sizeof( int );
        memcpy( newBufferPtr, nRings, sizeof( int ) );
        newBufferPtr += sizeof( int );

        for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
        {
          nPoints = ( int* )ptr;
          int newNPoints;
          if ( vertexnr >= pointindex && vertexnr < ( pointindex + ( *nPoints ) ) )//point is in this ring
          {
            newNPoints = ( *nPoints ) + 1;
          }
          else
          {
            newNPoints = *nPoints;
          }
          memcpy( newBufferPtr, &newNPoints, sizeof( double ) );
          newBufferPtr += sizeof( int );
          ptr += sizeof( int );

          for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
          {
            memcpy( newBufferPtr, ptr, sizeof( double ) );//x
            memcpy( newBufferPtr + sizeof( double ), ptr + sizeof( double ), sizeof( double ) );//y
            ptr += 2 * sizeof( double );
            newBufferPtr += 2 * sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
              newBufferPtr += sizeof( double );
            }
            ++pointindex;
            if ( pointindex == vertexnr )
            {
              memcpy( newBufferPtr, &x, sizeof( double ) );
              memcpy( newBufferPtr + sizeof( double ), &y, sizeof( double ) );
              newBufferPtr += 2 * sizeof( double );
              if ( hasZValue )
              {
                newBufferPtr += sizeof( double );
              }
              success = true;
            }
          }
        }

      }
      break;
    }
    case QGis::WKBNoGeometry:
    case QGis::WKBUnknown:
      break;
  }

  if ( success )
  {
    delete [] mGeometry;
    mGeometry = newbuffer;
    mGeometrySize += 2 * sizeof( double );
    if ( hasZValue )
    {
      mGeometrySize += sizeof( double );
    }
    mDirtyGeos = true;
    return true;
  }
  else
  {
    delete newbuffer;
    return false;
  }
}

QgsPoint QgsGeometry::vertexAt( int atVertex )
{
  double x, y;

  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return QgsPoint( 0, 0 );
  }

  QGis::WkbType wkbType;
  bool hasZValue = false;
  unsigned char* ptr;

  memcpy( &wkbType, ( mGeometry + 1 ), sizeof( int ) );
  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      if ( atVertex == 0 )
      {
        ptr = mGeometry + 1 + sizeof( int );
        memcpy( &x, ptr, sizeof( double ) );
        ptr += sizeof( double );
        memcpy( &y, ptr, sizeof( double ) );
        return QgsPoint( x, y );
      }
      else
      {
        return QgsPoint( 0, 0 );
      }
    }
    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      int *nPoints;
      // get number of points in the line
      ptr = mGeometry + 1 + sizeof( int );   // now at mGeometry.numPoints
      nPoints = ( int * ) ptr;

      // return error if underflow
      if ( 0 > atVertex || *nPoints <= atVertex )
      {
        return QgsPoint( 0, 0 );
      }

      // copy the vertex coordinates
      if ( hasZValue )
      {
        ptr = mGeometry + 9 + ( atVertex * 3 * sizeof( double ) );
      }
      else
      {
        ptr = mGeometry + 9 + ( atVertex * 2 * sizeof( double ) );
      }
      memcpy( &x, ptr, sizeof( double ) );
      ptr += sizeof( double );
      memcpy( &y, ptr, sizeof( double ) );
      return QgsPoint( x, y );
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int *nRings;
      int *nPoints = 0;
      ptr = mGeometry + 1 + sizeof( int );
      nRings = ( int* )ptr;
      ptr += sizeof( int );
      int pointindex = 0;
      for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
      {
        nPoints = ( int* )ptr;
        ptr += sizeof( int );
        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          if ( pointindex == atVertex )
          {
            memcpy( &x, ptr, sizeof( double ) );
            ptr += sizeof( double );
            memcpy( &y, ptr, sizeof( double ) );
            return QgsPoint( x, y );
          }
          ptr += 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          ++pointindex;
        }
      }
      return QgsPoint( 0, 0 );
    }
    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      ptr = mGeometry + 1 + sizeof( int );
      int* nPoints = ( int* )ptr;
      if ( atVertex < 0 || atVertex >= *nPoints )
      {
        return QgsPoint( 0, 0 );
      }
      if ( hasZValue )
      {
        ptr += atVertex * ( 3 * sizeof( double ) + 1 + sizeof( int ) );
      }
      else
      {
        ptr += atVertex * ( 2 * sizeof( double ) + 1 + sizeof( int ) );
      }
      ptr += 1 + sizeof( int );
      memcpy( &x, ptr, sizeof( double ) );
      ptr += sizeof( double );
      memcpy( &y, ptr, sizeof( double ) );
      return QgsPoint( x, y );
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      ptr = mGeometry + 1 + sizeof( int );
      int* nLines = ( int* )ptr;
      int* nPoints = 0; //number of points in a line
      int pointindex = 0; //global point counter
      ptr += sizeof( int );
      for ( int linenr = 0; linenr < *nLines; ++linenr )
      {
        ptr += sizeof( int ) + 1;
        nPoints = ( int* )ptr;
        ptr += sizeof( int );
        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          if ( pointindex == atVertex )
          {
            memcpy( &x, ptr, sizeof( double ) );
            ptr += sizeof( double );
            memcpy( &y, ptr, sizeof( double ) );
            return QgsPoint( x, y );
          }
          ptr += 2 * sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          ++pointindex;
        }
      }
      return QgsPoint( 0, 0 );
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      ptr = mGeometry + 1 + sizeof( int );
      int* nRings = 0;//number of rings in a polygon
      int* nPoints = 0;//number of points in a ring
      int pointindex = 0; //global point counter
      int* nPolygons = ( int* )ptr;
      ptr += sizeof( int );
      for ( int polynr = 0; polynr < *nPolygons; ++polynr )
      {
        ptr += ( 1 + sizeof( int ) ); //skip endian and polygon type
        nRings = ( int* )ptr;
        ptr += sizeof( int );
        for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
        {
          nPoints = ( int* )ptr;
          ptr += sizeof( int );
          for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
          {
            if ( pointindex == atVertex )
            {
              memcpy( &x, ptr, sizeof( double ) );
              ptr += sizeof( double );
              memcpy( &y, ptr, sizeof( double ) );
              return QgsPoint( x, y );
            }
            ++pointindex;
            ptr += 2 * sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
          }
        }
      }
      return QgsPoint( 0, 0 );
    }
    default:
      QgsDebugMsg( "error: mGeometry type not recognized" );
      return QgsPoint( 0, 0 );
  }
}


double QgsGeometry::sqrDistToVertexAt( QgsPoint& point, int atVertex )
{
  QgsPoint pnt = vertexAt( atVertex );
  if ( pnt != QgsPoint( 0, 0 ) )
  {
    QgsDebugMsg( "Exiting with distance to " + pnt.toString() );
    return point.sqrDist( pnt );
  }
  else
  {
    QgsDebugMsg( "Exiting with std::numeric_limits<double>::max()." );
    // probably safest to bail out with a very large number
    return std::numeric_limits<double>::max();
  }
}


double QgsGeometry::closestVertexWithContext( const QgsPoint& point, int& atVertex )
{
  double sqrDist = std::numeric_limits<double>::max();

  try
  {
    // Initialise some stuff
    int closestVertexIndex = 0;

    // set up the GEOS geometry
    if ( mDirtyGeos )
    {
      exportWkbToGeos();
    }

    if ( !mGeos )
    {
      return -1;
    }

    const GEOSGeometry *g = GEOSGetExteriorRing( mGeos );
    if ( !g )
      return -1;

    const GEOSCoordSequence *sequence = GEOSGeom_getCoordSeq( g );

    unsigned int n;
    GEOSCoordSeq_getSize( sequence, &n );

    for ( unsigned int i = 0; i < n; i++ )
    {
      double x, y;
      GEOSCoordSeq_getX( sequence, i, &x );
      GEOSCoordSeq_getY( sequence, i, &y );

      double testDist = point.sqrDist( x, y );
      if ( testDist < sqrDist )
      {
        closestVertexIndex = i;
        sqrDist = testDist;
      }
    }

    atVertex = closestVertexIndex;
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    return -1;
  }

  return sqrDist;
}


double QgsGeometry::closestSegmentWithContext(
  const QgsPoint& point,
  QgsPoint& minDistPoint,
  int& afterVertex,
  double* leftOf,
  double epsilon )
{
  QgsDebugMsg( "Entering." );
  QgsPoint distPoint;

  QGis::WkbType wkbType;
  bool hasZValue = false;
  double *thisx = NULL;
  double *thisy = NULL;
  double *prevx = NULL;
  double *prevy = NULL;
  double testdist;
  int closestSegmentIndex = 0;

  // Initialise some stuff
  double sqrDist = std::numeric_limits<double>::max();

  // TODO: implement with GEOS
  if ( mDirtyWkb ) //convert latest geos to mGeometry
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return -1;
  }

  memcpy( &wkbType, ( mGeometry + 1 ), sizeof( int ) );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    case QGis::WKBMultiPoint25D:
    case QGis::WKBMultiPoint:
    {
      // Points have no lines
      return -1;
    }
    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      unsigned char* ptr = mGeometry + 1 + sizeof( int );
      int* npoints = ( int* ) ptr;
      ptr += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        if ( index > 0 )
        {
          prevx = thisx;
          prevy = thisy;
        }
        thisx = ( double* ) ptr;
        ptr += sizeof( double );
        thisy = ( double* ) ptr;

        if ( index > 0 )
        {
          if (( testdist = point.sqrDistToSegment( *prevx, *prevy, *thisx, *thisy, distPoint, epsilon ) ) < sqrDist )
          {
            closestSegmentIndex = index;
            sqrDist = testdist;
            minDistPoint = distPoint;
            if ( leftOf )
            {
              *leftOf = QgsGeometry::leftOf( point.x(), point.y(), *prevx, *prevy, *thisx, *thisy );
            }
          }
        }
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
      }
      afterVertex = closestSegmentIndex;
      break;
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      unsigned char* ptr = mGeometry + 1 + sizeof( int );
      int* nLines = ( int* )ptr;
      ptr += sizeof( int );
      int* nPoints = 0; //number of points in a line
      int pointindex = 0;//global pointindex
      for ( int linenr = 0; linenr < *nLines; ++linenr )
      {
        ptr += sizeof( int ) + 1;
        nPoints = ( int* )ptr;
        ptr += sizeof( int );
        prevx = 0;
        prevy = 0;
        for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
        {
          thisx = ( double* ) ptr;
          ptr += sizeof( double );
          thisy = ( double* ) ptr;
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          if ( prevx && prevy )
          {
            if (( testdist = point.sqrDistToSegment( *prevx, *prevy, *thisx, *thisy, distPoint, epsilon ) ) < sqrDist )
            {
              closestSegmentIndex = pointindex;
              sqrDist = testdist;
              minDistPoint = distPoint;
              if ( leftOf )
              {
                *leftOf = QgsGeometry::leftOf( point.x(), point.y(), *prevx, *prevy, *thisx, *thisy );
              }
            }
          }
          prevx = thisx;
          prevy = thisy;
          ++pointindex;
        }
      }
      afterVertex = closestSegmentIndex;
      break;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int index = 0;
      unsigned char* ptr = mGeometry + 1 + sizeof( int );
      int* nrings = ( int* )ptr;
      int* npoints = 0; //number of points in a ring
      ptr += sizeof( int );
      for ( int ringnr = 0; ringnr < *nrings; ++ringnr )//loop over rings
      {
        npoints = ( int* )ptr;
        ptr += sizeof( int );
        prevx = 0;
        prevy = 0;
        for ( int pointnr = 0; pointnr < *npoints; ++pointnr )//loop over points in a ring
        {
          thisx = ( double* )ptr;
          ptr += sizeof( double );
          thisy = ( double* )ptr;
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          if ( prevx && prevy )
          {
            if (( testdist = point.sqrDistToSegment( *prevx, *prevy, *thisx, *thisy, distPoint, epsilon ) ) < sqrDist )
            {
              closestSegmentIndex = index;
              sqrDist = testdist;
              minDistPoint = distPoint;
              if ( leftOf )
              {
                *leftOf = QgsGeometry::leftOf( point.x(), point.y(), *prevx, *prevy, *thisx, *thisy );
              }
            }
          }
          prevx = thisx;
          prevy = thisy;
          ++index;
        }
      }
      afterVertex = closestSegmentIndex;
      break;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      unsigned char* ptr = mGeometry + 1 + sizeof( int );
      int* nRings = 0;
      int* nPoints = 0;
      int pointindex = 0;
      int* nPolygons = ( int* )ptr;
      ptr += sizeof( int );
      for ( int polynr = 0; polynr < *nPolygons; ++polynr )
      {
        ptr += ( 1 + sizeof( int ) );
        nRings = ( int* )ptr;
        ptr += sizeof( int );
        for ( int ringnr = 0; ringnr < *nRings; ++ringnr )
        {
          nPoints = ( int* )ptr;
          ptr += sizeof( int );
          prevx = 0;
          prevy = 0;
          for ( int pointnr = 0; pointnr < *nPoints; ++pointnr )
          {
            thisx = ( double* )ptr;
            ptr += sizeof( double );
            thisy = ( double* )ptr;
            ptr += sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
            if ( prevx && prevy )
            {
              if (( testdist = point.sqrDistToSegment( *prevx, *prevy, *thisx, *thisy, distPoint, epsilon ) ) < sqrDist )
              {
                closestSegmentIndex = pointindex;
                sqrDist = testdist;
                minDistPoint = distPoint;
                if ( leftOf )
                {
                  *leftOf = QgsGeometry::leftOf( point.x(), point.y(), *prevx, *prevy, *thisx, *thisy );
                }
              }
            }
            prevx = thisx;
            prevy = thisy;
            ++pointindex;
          }
        }
      }
      afterVertex = closestSegmentIndex;
      break;
    }
    case QGis::WKBUnknown:
    default:
      return -1;
      break;
  } // switch (wkbType)


  QgsDebugMsg( QString( "Exiting with nearest point %1, dist %2." )
               .arg( point.toString() ).arg( sqrDist ) );

  return sqrDist;
}

int QgsGeometry::addRing( const QList<QgsPoint>& ring )
{
  //bail out if this geometry is not polygon/multipolygon
  if ( type() != QGis::Polygon )
    return 1;

  //test for invalid geometries
  if ( ring.size() < 4 )
    return 3;

  //ring must be closed
  if ( ring.first() != ring.last() )
    return 2;

  //create geos geometry from wkb if not already there
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 6;
  }

  int type = GEOSGeomTypeId( mGeos );

  //Fill GEOS Polygons of the feature into list
  QVector<const GEOSGeometry*> polygonList;

  if ( wkbType() == QGis::WKBPolygon )
  {
    if ( type != GEOS_POLYGON )
      return 1;

    polygonList << mGeos;
  }
  else if ( wkbType() == QGis::WKBMultiPolygon )
  {
    if ( type != GEOS_MULTIPOLYGON )
      return 1;

    for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); ++i )
      polygonList << GEOSGetGeometryN( mGeos, i );
  }

  //create new ring
  GEOSGeometry *newRing = 0;
  GEOSGeometry *newRingPolygon = 0;

  try
  {
    newRing = createGeosLinearRing( ring.toVector() );
    if ( !GEOSisValid( newRing ) )
    {
      throwGEOSException( "ring is invalid" );
    }

    newRingPolygon = createGeosPolygon( newRing );
    if ( !GEOSisValid( newRingPolygon ) )
    {
      throwGEOSException( "ring is invalid" );
    }
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

    if ( newRingPolygon )
      GEOSGeom_destroy( newRingPolygon );
    else if ( newRing )
      GEOSGeom_destroy( newRing );

    return 3;
  }

  QVector<GEOSGeometry*> rings;

  int i;
  for ( i = 0; i < polygonList.size(); i++ )
  {
    for ( int j = 0; j < rings.size(); j++ )
      GEOSGeom_destroy( rings[j] );
    rings.clear();

    GEOSGeometry *shellRing = 0;
    GEOSGeometry *shell = 0;
    try
    {
      shellRing = GEOSGeom_clone( GEOSGetExteriorRing( polygonList[i] ) );
      shell = createGeosPolygon( shellRing );

      if ( !GEOSWithin( newRingPolygon, shell ) )
      {
        GEOSGeom_destroy( shell );
        continue;
      }
    }
    catch ( GEOSException &e )
    {
      QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

      if ( shell )
        GEOSGeom_destroy( shell );
      else if ( shellRing )
        GEOSGeom_destroy( shellRing );

      GEOSGeom_destroy( newRingPolygon );

      return 4;
    }

    // add outer ring
    rings << GEOSGeom_clone( shellRing );

    GEOSGeom_destroy( shell );

    // check inner rings
    int n = GEOSGetNumInteriorRings( polygonList[i] );

    int j;
    for ( j = 0; j < n; j++ )
    {
      GEOSGeometry *holeRing = 0;
      GEOSGeometry *hole = 0;
      try
      {
        holeRing = GEOSGeom_clone( GEOSGetInteriorRingN( polygonList[i], j ) );
        hole = createGeosPolygon( holeRing );

        if ( !GEOSDisjoint( hole, newRingPolygon ) )
        {
          GEOSGeom_destroy( hole );
          break;
        }
      }
      catch ( GEOSException &e )
      {
        QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

        if ( hole )
          GEOSGeom_destroy( hole );
        else if ( holeRing )
          GEOSGeom_destroy( holeRing );

        break;
      }

      rings << GEOSGeom_clone( holeRing );
      GEOSGeom_destroy( hole );
    }

    if ( j == n )
      // this is it...
      break;
  }

  if ( i == polygonList.size() )
  {
    // clear rings
    for ( int j = 0; j < rings.size(); j++ )
      GEOSGeom_destroy( rings[j] );
    rings.clear();

    GEOSGeom_destroy( newRingPolygon );

    // no containing polygon found
    return 5;
  }

  rings << GEOSGeom_clone( newRing );
  GEOSGeom_destroy( newRingPolygon );

  GEOSGeometry *newPolygon = createGeosPolygon( rings );

  if ( wkbType() == QGis::WKBPolygon )
  {
    GEOSGeom_destroy( mGeos );
    mGeos = newPolygon;
  }
  else if ( wkbType() == QGis::WKBMultiPolygon )
  {
    QVector<GEOSGeometry*> newPolygons;

    for ( int j = 0; j < polygonList.size(); j++ )
    {
      newPolygons << ( i == j ? newPolygon : GEOSGeom_clone( polygonList[j] ) );
    }

    GEOSGeom_destroy( mGeos );
    mGeos = createGeosCollection( GEOS_MULTIPOLYGON, newPolygons );
  }

  mDirtyWkb = true;
  mDirtyGeos = false;
  return 0;
}

int QgsGeometry::addPart( const QList<QgsPoint> &points )
{
  QGis::GeometryType geomType = type();

  switch ( geomType )
  {
    case QGis::Point:
      // only one part at a time
      if ( points.size() != 1 )
      {
        QgsDebugMsg( "expected 1 point: " + QString::number( points.size() ) );
        return 2;
      }
      break;

    case QGis::Line:
      // Line needs to have at least two points and must be closed
      if ( points.size() < 3 )
      {
        QgsDebugMsg( "line must at least have two points: " + QString::number( points.size() ) );
        return 2;
      }
      break;

    case QGis::Polygon:
      // Ring needs to have at least three points and must be closed
      if ( points.size() < 4 )
      {
        QgsDebugMsg( "polygon must at least have three points: " + QString::number( points.size() ) );
        return 2;
      }

      // ring must be closed
      if ( points.first() != points.last() )
      {
        QgsDebugMsg( "polygon not closed" );
        return 2;
      }
      break;

    default:
      QgsDebugMsg( "unsupported geometry type: " + QString::number( geomType ) );
      return 2;
  }

  if ( !isMultipart() && !convertToMultiType() )
  {
    QgsDebugMsg( "could not convert to multipart" );
    return 1;
  }

  //create geos geometry from wkb if not already there
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    QgsDebugMsg( "GEOS geometry not available!" );
    return 4;
  }

  int geosType = GEOSGeomTypeId( mGeos );
  GEOSGeometry *newPart = 0;

  switch ( geomType )
  {
    case QGis::Point:
      newPart = createGeosPoint( points[0] );
      break;

    case QGis::Line:
      newPart = createGeosLineString( points.toVector() );
      break;

    case QGis::Polygon:
    {
      //create new polygon from ring
      GEOSGeometry *newRing = 0;

      try
      {
        newRing = createGeosLinearRing( points.toVector() );
        if ( !GEOSisValid( newRing ) )
          throw GEOSException( "ring invalid" );

        newPart = createGeosPolygon( newRing );
      }
      catch ( GEOSException &e )
      {
        QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

        if ( newRing )
          GEOSGeom_destroy( newRing );

        return 2;
      }
    }
    break;

    default:
      QgsDebugMsg( "unsupported type: " + QString::number( type() ) );
      return 2;
  }

  Q_ASSERT( newPart );

  try
  {
    if ( !GEOSisValid( newPart ) )
      throw GEOSException( "new part geometry invalid" );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );

    if ( newPart )
      GEOSGeom_destroy( newPart );

    QgsDebugMsg( "part invalid: " + e.what() );
    return 2;
  }

  QVector<GEOSGeometry*> parts;

  //create new multipolygon
  int n = GEOSGetNumGeometries( mGeos );
  int i;
  for ( i = 0; i < n; ++i )
  {
    const GEOSGeometry *partN = GEOSGetGeometryN( mGeos, i );

    if ( geomType == QGis::Polygon && !GEOSDisjoint( partN, newPart ) )
      //bail out if new polygon is not disjoint with existing ones
      break;

    parts << GEOSGeom_clone( partN );
  }

  if ( i < n )
  {
    // bailed out
    for ( int i = 0; i < parts.size(); i++ )
      GEOSGeom_destroy( parts[i] );

    QgsDebugMsg( "new polygon part not disjoint" );
    return 3;
  }

  parts << newPart;

  GEOSGeom_destroy( mGeos );

  mGeos = createGeosCollection( geosType, parts );

  mDirtyWkb = true;
  mDirtyGeos = false;

  return 0;
}

int QgsGeometry::translate( double dx, double dy )
{
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return 1;
  }

  QGis::WkbType wkbType;
  memcpy( &wkbType, &( mGeometry[1] ), sizeof( int ) );
  bool hasZValue = false;
  int wkbPosition = 5;

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      translateVertex( wkbPosition, dx, dy, hasZValue );
    }
    break;

    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      int* npoints = ( int* )( &mGeometry[wkbPosition] );
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        translateVertex( wkbPosition, dx, dy, hasZValue );
      }
      break;
    }

    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nrings = ( int* )( &( mGeometry[wkbPosition] ) );
      wkbPosition += sizeof( int );
      int* npoints;

      for ( int index = 0; index < *nrings; ++index )
      {
        npoints = ( int* )( &( mGeometry[wkbPosition] ) );
        wkbPosition += sizeof( int );
        for ( int index2 = 0; index2 < *npoints; ++index2 )
        {
          translateVertex( wkbPosition, dx, dy, hasZValue );
        }
      }
      break;
    }

    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      int* npoints = ( int* )( &( mGeometry[wkbPosition] ) );
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        wkbPosition += ( sizeof( int ) + 1 );
        translateVertex( wkbPosition, dx, dy, hasZValue );
      }
      break;
    }

    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      int* nlines = ( int* )( &( mGeometry[wkbPosition] ) );
      int* npoints = 0;
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *nlines; ++index )
      {
        wkbPosition += ( sizeof( int ) + 1 );
        npoints = ( int* )( &( mGeometry[wkbPosition] ) );
        wkbPosition += sizeof( int );
        for ( int index2 = 0; index2 < *npoints; ++index2 )
        {
          translateVertex( wkbPosition, dx, dy, hasZValue );
        }
      }
      break;
    }

    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      int* npolys = ( int* )( &( mGeometry[wkbPosition] ) );
      int* nrings;
      int* npoints;
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *npolys; ++index )
      {
        wkbPosition += ( 1 + sizeof( int ) ); //skip endian and polygon type
        nrings = ( int* )( &( mGeometry[wkbPosition] ) );
        wkbPosition += sizeof( int );
        for ( int index2 = 0; index2 < *nrings; ++index2 )
        {
          npoints = ( int* )( &( mGeometry[wkbPosition] ) );
          wkbPosition += sizeof( int );
          for ( int index3 = 0; index3 < *npoints; ++index3 )
          {
            translateVertex( wkbPosition, dx, dy, hasZValue );
          }
        }
      }
    }

    default:
      break;
  }
  mDirtyGeos = true;
  return 0;
}

int QgsGeometry::transform( const QgsCoordinateTransform& ct )
{
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return 1;
  }

  QGis::WkbType wkbType;
  memcpy( &wkbType, &( mGeometry[1] ), sizeof( int ) );
  bool hasZValue = false;
  int wkbPosition = 5;

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      transformVertex( wkbPosition, ct, hasZValue );
    }
    break;

    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      int* npoints = ( int* )( &mGeometry[wkbPosition] );
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        transformVertex( wkbPosition, ct, hasZValue );
      }
      break;
    }

    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      int* nrings = ( int* )( &( mGeometry[wkbPosition] ) );
      wkbPosition += sizeof( int );
      int* npoints;

      for ( int index = 0; index < *nrings; ++index )
      {
        npoints = ( int* )( &( mGeometry[wkbPosition] ) );
        wkbPosition += sizeof( int );
        for ( int index2 = 0; index2 < *npoints; ++index2 )
        {
          transformVertex( wkbPosition, ct, hasZValue );
        }
      }
      break;
    }

    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      int* npoints = ( int* )( &( mGeometry[wkbPosition] ) );
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *npoints; ++index )
      {
        wkbPosition += ( sizeof( int ) + 1 );
        transformVertex( wkbPosition, ct, hasZValue );
      }
      break;
    }

    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      int* nlines = ( int* )( &( mGeometry[wkbPosition] ) );
      int* npoints = 0;
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *nlines; ++index )
      {
        wkbPosition += ( sizeof( int ) + 1 );
        npoints = ( int* )( &( mGeometry[wkbPosition] ) );
        wkbPosition += sizeof( int );
        for ( int index2 = 0; index2 < *npoints; ++index2 )
        {
          transformVertex( wkbPosition, ct, hasZValue );
        }
      }
      break;
    }

    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      int* npolys = ( int* )( &( mGeometry[wkbPosition] ) );
      int* nrings;
      int* npoints;
      wkbPosition += sizeof( int );
      for ( int index = 0; index < *npolys; ++index )
      {
        wkbPosition += ( 1 + sizeof( int ) ); //skip endian and polygon type
        nrings = ( int* )( &( mGeometry[wkbPosition] ) );
        wkbPosition += sizeof( int );
        for ( int index2 = 0; index2 < *nrings; ++index2 )
        {
          npoints = ( int* )( &( mGeometry[wkbPosition] ) );
          wkbPosition += sizeof( int );
          for ( int index3 = 0; index3 < *npoints; ++index3 )
          {
            transformVertex( wkbPosition, ct, hasZValue );
          }
        }
      }
    }

    default:
      break;
  }
  mDirtyGeos = true;
  return 0;
}

int QgsGeometry::splitGeometry( const QList<QgsPoint>& splitLine, QList<QgsGeometry*>& newGeometries, bool topological, QList<QgsPoint> &topologyTestPoints )
{
  int returnCode = 0;

  //return if this type is point/multipoint
  if ( type() == QGis::Point )
  {
    return 1; //cannot split points
  }

  //make sure, mGeos and mWkb are there and up-to-date
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 1;
  }

  if ( !GEOSisValid( mGeos ) )
  {
    return 7;
  }

  //make sure splitLine is valid
  if ( splitLine.size() < 2 )
  {
    return 1;
  }

  newGeometries.clear();

  try
  {
    GEOSGeometry *splitLineGeos = createGeosLineString( splitLine.toVector() );
    if ( !GEOSisValid( splitLineGeos ) || !GEOSisSimple( splitLineGeos ) )
    {
      GEOSGeom_destroy( splitLineGeos );
      return 1;
    }

    if ( topological )
    {
      //find out candidate points for topological corrections
      if ( topologicalTestPointsSplit( splitLineGeos, topologyTestPoints ) != 0 )
      {
        return 1;
      }
    }

    //call split function depending on geometry type
    if ( type() == QGis::Line )
    {
      returnCode = splitLinearGeometry( splitLineGeos, newGeometries );
      GEOSGeom_destroy( splitLineGeos );
    }
    else if ( type() == QGis::Polygon )
    {
      returnCode = splitPolygonGeometry( splitLineGeos, newGeometries );
      GEOSGeom_destroy( splitLineGeos );
    }
    else
    {
      return 1;
    }
  }
  CATCH_GEOS( 2 )

  return returnCode;
}

int QgsGeometry::reshapeGeometry( const QList<QgsPoint>& reshapeWithLine )
{
  if ( reshapeWithLine.size() < 2 )
  {
    return 1;
  }

  if ( type() == QGis::Point )
  {
    return 1; //cannot reshape points
  }

  GEOSGeometry* reshapeLineGeos = createGeosLineString( reshapeWithLine.toVector() );

  //make sure this geos geometry is up-to-date
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 1;
  }

  //single or multi?
  int numGeoms = GEOSGetNumGeometries( mGeos );
  if ( numGeoms == -1 )
  {
    return 1;
  }

  bool isMultiGeom = false;
  int geosTypeId = GEOSGeomTypeId( mGeos );
  if ( geosTypeId == GEOS_MULTILINESTRING || geosTypeId == GEOS_MULTIPOLYGON )
  {
    isMultiGeom = true;
  }

  bool isLine = ( type() == QGis::Line );

  //polygon or multipolygon?
  if ( !isMultiGeom )
  {
    GEOSGeometry* reshapedGeometry;
    if ( isLine )
    {
      reshapedGeometry = reshapeLine( mGeos, reshapeLineGeos );
    }
    else
    {
      reshapedGeometry = reshapePolygon( mGeos, reshapeLineGeos );
    }

    GEOSGeom_destroy( reshapeLineGeos );
    if ( reshapedGeometry )
    {
      GEOSGeom_destroy( mGeos );
      mGeos = reshapedGeometry;
      mDirtyWkb = true;
      return 0;
    }
    else
    {
      return 1;
    }
  }
  else
  {
    //call reshape for each geometry part and replace mGeos with new geometry if reshape took place
    bool reshapeTookPlace = false;

    GEOSGeometry* currentReshapeGeometry = 0;
    GEOSGeometry** newGeoms = new GEOSGeometry*[numGeoms];

    for ( int i = 0; i < numGeoms; ++i )
    {
      if ( isLine )
      {
        currentReshapeGeometry = reshapeLine( GEOSGetGeometryN( mGeos, i ), reshapeLineGeos );
      }
      else
      {
        currentReshapeGeometry = reshapePolygon( GEOSGetGeometryN( mGeos, i ), reshapeLineGeos );
      }

      if ( currentReshapeGeometry )
      {
        newGeoms[i] = currentReshapeGeometry;
        reshapeTookPlace = true;
      }
      else
      {
        newGeoms[i] = GEOSGeom_clone( GEOSGetGeometryN( mGeos, i ) );
      }
    }
    GEOSGeom_destroy( reshapeLineGeos );

    GEOSGeometry* newMultiGeom = 0;
    if ( isLine )
    {
      newMultiGeom = GEOSGeom_createCollection( GEOS_MULTILINESTRING, newGeoms, numGeoms );
    }
    else //multipolygon
    {
      newMultiGeom = GEOSGeom_createCollection( GEOS_MULTIPOLYGON, newGeoms, numGeoms );
    }

    delete[] newGeoms;
    if ( ! newMultiGeom )
    {
      return 3;
    }

    if ( reshapeTookPlace )
    {
      GEOSGeom_destroy( mGeos );
      mGeos = newMultiGeom;
      mDirtyWkb = true;
      return 0;
    }
    else
    {
      GEOSGeom_destroy( newMultiGeom );
      return 1;
    }
  }
}

int QgsGeometry::makeDifference( QgsGeometry* other )
{
  //make sure geos geometry is up to date
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 1;
  }

  if ( !GEOSisValid( mGeos ) )
  {
    return 2;
  }

  if ( !GEOSisSimple( mGeos ) )
  {
    return 3;
  }

  //convert other geometry to geos
  if ( other->mDirtyGeos )
  {
    other->exportWkbToGeos();
  }

  if ( !other->mGeos )
  {
    return 4;
  }

  //make geometry::difference
  try
  {
    if ( GEOSIntersects( mGeos, other->mGeos ) )
    {
      //check if multitype before and after
      bool multiType = isMultipart();

      mGeos = GEOSDifference( mGeos, other->mGeos );
      mDirtyWkb = true;

      if ( multiType && !isMultipart() )
      {
        convertToMultiType();
        exportWkbToGeos();
      }
    }
    else
    {
      return 0; //nothing to do
    }
  }
  CATCH_GEOS( 5 )

  if ( !mGeos )
  {
    mDirtyGeos = true;
    return 6;
  }

  return 0;
}

QgsRectangle QgsGeometry::boundingBox()
{
  double xmin =  std::numeric_limits<double>::max();
  double ymin =  std::numeric_limits<double>::max();
  double xmax = -std::numeric_limits<double>::max();
  double ymax = -std::numeric_limits<double>::max();

  double *x;
  double *y;
  int *nPoints;
  int *numRings;
  int *numPolygons;
  int numLineStrings;
  int idx, jdx, kdx;
  unsigned char *ptr;
  QgsPoint pt;
  QGis::WkbType wkbType;
  bool hasZValue = false;

  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return QgsRectangle( 0, 0, 0, 0 );
  }

  // consider endian when fetching feature type
  //wkbType = (mGeometry[0] == 1) ? mGeometry[1] : mGeometry[4]; //MH: Does not work for 25D geometries
  memcpy( &wkbType, &( mGeometry[1] ), sizeof( int ) );
  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
      x = ( double * )( mGeometry + 5 );
      y = ( double * )( mGeometry + 5 + sizeof( double ) );
      if ( *x < xmin )
      {
        xmin = *x;
      }
      if ( *x > xmax )
      {
        xmax = *x;
      }
      if ( *y < ymin )
      {
        ymin = *y;
      }
      if ( *y > ymax )
      {
        ymax = *y;
      }
      break;
    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      ptr = mGeometry + 1 + sizeof( int );
      nPoints = ( int * ) ptr;
      ptr += sizeof( int );
      for ( idx = 0; idx < *nPoints; idx++ )
      {
        ptr += ( 1 + sizeof( int ) );
        x = ( double * ) ptr;
        ptr += sizeof( double );
        y = ( double * ) ptr;
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
        if ( *x < xmin )
        {
          xmin = *x;
        }
        if ( *x > xmax )
        {
          xmax = *x;
        }
        if ( *y < ymin )
        {
          ymin = *y;
        }
        if ( *y > ymax )
        {
          ymax = *y;
        }
      }
      break;
    }
    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      // get number of points in the line
      ptr = mGeometry + 5;
      nPoints = ( int * ) ptr;
      ptr = mGeometry + 1 + 2 * sizeof( int );
      for ( idx = 0; idx < *nPoints; idx++ )
      {
        x = ( double * ) ptr;
        ptr += sizeof( double );
        y = ( double * ) ptr;
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
        if ( *x < xmin )
        {
          xmin = *x;
        }
        if ( *x > xmax )
        {
          xmax = *x;
        }
        if ( *y < ymin )
        {
          ymin = *y;
        }
        if ( *y > ymax )
        {
          ymax = *y;
        }
      }
      break;
    }
    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      numLineStrings = ( int )( mGeometry[5] );
      ptr = mGeometry + 9;
      for ( jdx = 0; jdx < numLineStrings; jdx++ )
      {
        // each of these is a wbklinestring so must handle as such
        ptr += 5;   // skip type since we know its 2
        nPoints = ( int * ) ptr;
        ptr += sizeof( int );
        for ( idx = 0; idx < *nPoints; idx++ )
        {
          x = ( double * ) ptr;
          ptr += sizeof( double );
          y = ( double * ) ptr;
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          if ( *x < xmin )
          {
            xmin = *x;
          }
          if ( *x > xmax )
          {
            xmax = *x;
          }
          if ( *y < ymin )
          {
            ymin = *y;
          }
          if ( *y > ymax )
          {
            ymax = *y;
          }
        }
      }
      break;
    }
    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      // get number of rings in the polygon
      numRings = ( int * )( mGeometry + 1 + sizeof( int ) );
      ptr = mGeometry + 1 + 2 * sizeof( int );
      for ( idx = 0; idx < *numRings; idx++ )
      {
        // get number of points in the ring
        nPoints = ( int * ) ptr;
        ptr += 4;
        for ( jdx = 0; jdx < *nPoints; jdx++ )
        {
          // add points to a point array for drawing the polygon
          x = ( double * ) ptr;
          ptr += sizeof( double );
          y = ( double * ) ptr;
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          if ( *x < xmin )
          {
            xmin = *x;
          }
          if ( *x > xmax )
          {
            xmax = *x;
          }
          if ( *y < ymin )
          {
            ymin = *y;
          }
          if ( *y > ymax )
          {
            ymax = *y;
          }
        }
      }
      break;
    }
    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      // get the number of polygons
      ptr = mGeometry + 5;
      numPolygons = ( int * ) ptr;
      ptr += 4;

      for ( kdx = 0; kdx < *numPolygons; kdx++ )
      {
        //skip the endian and mGeometry type info and
        // get number of rings in the polygon
        ptr += 5;
        numRings = ( int * ) ptr;
        ptr += 4;
        for ( idx = 0; idx < *numRings; idx++ )
        {
          // get number of points in the ring
          nPoints = ( int * ) ptr;
          ptr += 4;
          for ( jdx = 0; jdx < *nPoints; jdx++ )
          {
            // add points to a point array for drawing the polygon
            x = ( double * ) ptr;
            ptr += sizeof( double );
            y = ( double * ) ptr;
            ptr += sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
            if ( *x < xmin )
            {
              xmin = *x;
            }
            if ( *x > xmax )
            {
              xmax = *x;
            }
            if ( *y < ymin )
            {
              ymin = *y;
            }
            if ( *y > ymax )
            {
              ymax = *y;
            }
          }
        }
      }
      break;
    }

    default:
      QgsDebugMsg( QString( "Unknown WkbType %1 ENCOUNTERED" ).arg( wkbType ) );
      return QgsRectangle( 0, 0, 0, 0 );
      break;

  }
  return QgsRectangle( xmin, ymin, xmax, ymax );
}

bool QgsGeometry::intersects( const QgsRectangle& r )
{
  QgsGeometry* g = fromRect( r );
  bool res = intersects( g );
  delete g;
  return res;
}

bool QgsGeometry::intersects( QgsGeometry* geometry )
{
  try // geos might throw exception on error
  {
    // ensure that both geometries have geos geometry
    exportWkbToGeos();
    geometry->exportWkbToGeos();

    if ( !mGeos || !geometry->mGeos )
    {
      QgsDebugMsg( "GEOS geometry not available!" );
      return false;
    }

    return GEOSIntersects( mGeos, geometry->mGeos );
  }
  CATCH_GEOS( false )
}


bool QgsGeometry::contains( QgsPoint* p )
{
  exportWkbToGeos();

  if ( !mGeos )
  {
    QgsDebugMsg( "GEOS geometry not available!" );
    return false;
  }

  GEOSGeometry *geosPoint = 0;

  bool returnval = false;

  try
  {
    geosPoint = createGeosPoint( *p );
    returnval = GEOSContains( mGeos, geosPoint );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    returnval = false;
  }

  if ( geosPoint )
    GEOSGeom_destroy( geosPoint );

  return returnval;
}

bool QgsGeometry::geosRelOp(
  char( *op )( const GEOSGeometry*, const GEOSGeometry * ),
  QgsGeometry *a,
  QgsGeometry *b )
{
  try // geos might throw exception on error
  {
    // ensure that both geometries have geos geometry
    a->exportWkbToGeos();
    b->exportWkbToGeos();

    if ( !a->mGeos || !b->mGeos )
    {
      QgsDebugMsg( "GEOS geometry not available!" );
      return false;
    }
    return op( a->mGeos, b->mGeos );
  }
  CATCH_GEOS( false )
}

bool QgsGeometry::contains( QgsGeometry* geometry )
{
  return geosRelOp( GEOSContains, this, geometry );
}

bool QgsGeometry::disjoint( QgsGeometry* geometry )
{
  return geosRelOp( GEOSDisjoint, this, geometry );
}

bool QgsGeometry::equals( QgsGeometry* geometry )
{
  return geosRelOp( GEOSEquals, this, geometry );
}

bool QgsGeometry::touches( QgsGeometry* geometry )
{
  return geosRelOp( GEOSTouches, this, geometry );
}

bool QgsGeometry::overlaps( QgsGeometry* geometry )
{
  return geosRelOp( GEOSOverlaps, this, geometry );
}

bool QgsGeometry::within( QgsGeometry* geometry )
{
  return geosRelOp( GEOSWithin, this, geometry );
}

bool QgsGeometry::crosses( QgsGeometry* geometry )
{
  return geosRelOp( GEOSCrosses, this, geometry );
}

QString QgsGeometry::exportToWkt()
{
  QgsDebugMsg( "entered." );

  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry || wkbSize() < 5 )
  {
    QgsDebugMsg( "WKB geometry not available or too short!" );
    return QString::null;
  }

  QGis::WkbType wkbType;
  bool hasZValue = false;
  double *x, *y;

  QString mWkt; // TODO: rename

  // Will this really work when mGeometry[0] == 0 ???? I (gavin) think not.
  //wkbType = (mGeometry[0] == 1) ? mGeometry[1] : mGeometry[4];
  memcpy( &wkbType, &( mGeometry[1] ), sizeof( int ) );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      mWkt += "POINT(";
      x = ( double * )( mGeometry + 5 );
      mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
      mWkt += " ";
      y = ( double * )( mGeometry + 5 + sizeof( double ) );
      mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
      mWkt += ")";
      return mWkt;
    }

    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      QgsDebugMsg( "LINESTRING found" );
      unsigned char *ptr;
      int *nPoints;
      int idx;

      mWkt += "LINESTRING(";
      // get number of points in the line
      ptr = mGeometry + 5;
      nPoints = ( int * ) ptr;
      ptr = mGeometry + 1 + 2 * sizeof( int );
      for ( idx = 0; idx < *nPoints; ++idx )
      {
        if ( idx != 0 )
        {
          mWkt += ", ";
        }
        x = ( double * ) ptr;
        mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        mWkt += " ";
        ptr += sizeof( double );
        y = ( double * ) ptr;
        mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
      }
      mWkt += ")";
      return mWkt;
    }

    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      QgsDebugMsg( "POLYGON found" );
      unsigned char *ptr;
      int idx, jdx;
      int *numRings, *nPoints;

      mWkt += "POLYGON(";
      // get number of rings in the polygon
      numRings = ( int * )( mGeometry + 1 + sizeof( int ) );
      if ( !( *numRings ) )  // sanity check for zero rings in polygon
      {
        return QString();
      }
      int *ringStart; // index of first point for each ring
      int *ringNumPoints; // number of points in each ring
      ringStart = new int[*numRings];
      ringNumPoints = new int[*numRings];
      ptr = mGeometry + 1 + 2 * sizeof( int ); // set pointer to the first ring
      for ( idx = 0; idx < *numRings; idx++ )
      {
        if ( idx != 0 )
        {
          mWkt += ",";
        }
        mWkt += "(";
        // get number of points in the ring
        nPoints = ( int * ) ptr;
        ringNumPoints[idx] = *nPoints;
        ptr += 4;

        for ( jdx = 0; jdx < *nPoints; jdx++ )
        {
          if ( jdx != 0 )
          {
            mWkt += ",";
          }
          x = ( double * ) ptr;
          mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          mWkt += " ";
          ptr += sizeof( double );
          y = ( double * ) ptr;
          mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
        }
        mWkt += ")";
      }
      mWkt += ")";
      delete [] ringStart;
      delete [] ringNumPoints;
      return mWkt;
    }

    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      unsigned char *ptr;
      int idx;
      int *nPoints;

      mWkt += "MULTIPOINT(";
      nPoints = ( int* )( mGeometry + 5 );
      ptr = mGeometry + 5 + sizeof( int );
      for ( idx = 0; idx < *nPoints; ++idx )
      {
        ptr += ( 1 + sizeof( int ) );
        if ( idx != 0 )
        {
          mWkt += ", ";
        }
        x = ( double * )( ptr );
        mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        mWkt += " ";
        ptr += sizeof( double );
        y = ( double * )( ptr );
        mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
      }
      mWkt += ")";
      return mWkt;
    }

    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      QgsDebugMsg( "MULTILINESTRING found" );
      unsigned char *ptr;
      int idx, jdx, numLineStrings;
      int *nPoints;

      mWkt += "MULTILINESTRING(";
      numLineStrings = ( int )( mGeometry[5] );
      ptr = mGeometry + 9;
      for ( jdx = 0; jdx < numLineStrings; jdx++ )
      {
        if ( jdx != 0 )
        {
          mWkt += ", ";
        }
        mWkt += "(";
        ptr += 5; // skip type since we know its 2
        nPoints = ( int * ) ptr;
        ptr += sizeof( int );
        for ( idx = 0; idx < *nPoints; idx++ )
        {
          if ( idx != 0 )
          {
            mWkt += ", ";
          }
          x = ( double * ) ptr;
          mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          ptr += sizeof( double );
          mWkt += " ";
          y = ( double * ) ptr;
          mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
        }
        mWkt += ")";
      }
      mWkt += ")";
      return mWkt;
    }

    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      QgsDebugMsg( "MULTIPOLYGON found" );
      unsigned char *ptr;
      int idx, jdx, kdx;
      int *numPolygons, *numRings, *nPoints;

      mWkt += "MULTIPOLYGON(";
      ptr = mGeometry + 5;
      numPolygons = ( int * ) ptr;
      ptr = mGeometry + 9;
      for ( kdx = 0; kdx < *numPolygons; kdx++ )
      {
        if ( kdx != 0 )
        {
          mWkt += ",";
        }
        mWkt += "(";
        ptr += 5;
        numRings = ( int * ) ptr;
        ptr += 4;
        for ( idx = 0; idx < *numRings; idx++ )
        {
          if ( idx != 0 )
          {
            mWkt += ",";
          }
          mWkt += "(";
          nPoints = ( int * ) ptr;
          ptr += 4;
          for ( jdx = 0; jdx < *nPoints; jdx++ )
          {
            if ( jdx != 0 )
            {
              mWkt += ",";
            }
            x = ( double * ) ptr;
            mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
            ptr += sizeof( double );
            mWkt += " ";
            y = ( double * ) ptr;
            mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
            ptr += sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
          }
          mWkt += ")";
        }
        mWkt += ")";
      }
      mWkt += ")";
      return mWkt;
    }

    default:
      QgsDebugMsg( "error: mGeometry type not recognized" );
      return QString::null;
  }
}

QString QgsGeometry::exportToGeoJSON()
{
  QgsDebugMsg( "entered." );

  // TODO: implement with GEOS
  if ( mDirtyWkb )
  {
    exportGeosToWkb();
  }

  if ( !mGeometry )
  {
    QgsDebugMsg( "WKB geometry not available!" );
    return QString::null;
  }

  QGis::WkbType wkbType;
  bool hasZValue = false;
  double *x, *y;

  QString mWkt; // TODO: rename

  // Will this really work when mGeometry[0] == 0 ???? I (gavin) think not.
  //wkbType = (mGeometry[0] == 1) ? mGeometry[1] : mGeometry[4];
  memcpy( &wkbType, &( mGeometry[1] ), sizeof( int ) );

  switch ( wkbType )
  {
    case QGis::WKBPoint25D:
    case QGis::WKBPoint:
    {
      mWkt += "{ \"type\": \"Point\", \"coordinates\": [";
      x = ( double * )( mGeometry + 5 );
      mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
      mWkt += ", ";
      y = ( double * )( mGeometry + 5 + sizeof( double ) );
      mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
      mWkt += "] }";
      return mWkt;
    }

    case QGis::WKBLineString25D:
      hasZValue = true;
    case QGis::WKBLineString:
    {
      QgsDebugMsg( "LINESTRING found" );
      unsigned char *ptr;
      int *nPoints;
      int idx;

      mWkt += "{ \"type\": \"LineString\", \"coordinates\": [ ";
      // get number of points in the line
      ptr = mGeometry + 5;
      nPoints = ( int * ) ptr;
      ptr = mGeometry + 1 + 2 * sizeof( int );
      for ( idx = 0; idx < *nPoints; ++idx )
      {
        if ( idx != 0 )
        {
          mWkt += ", ";
        }
        mWkt += "[";
        x = ( double * ) ptr;
        mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        mWkt += ", ";
        ptr += sizeof( double );
        y = ( double * ) ptr;
        mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
        mWkt += "]";
      }
      mWkt += " ] }";
      return mWkt;
    }

    case QGis::WKBPolygon25D:
      hasZValue = true;
    case QGis::WKBPolygon:
    {
      QgsDebugMsg( "POLYGON found" );
      unsigned char *ptr;
      int idx, jdx;
      int *numRings, *nPoints;

      mWkt += "{ \"type\": \"Polygon\", \"coordinates\": [ ";
      // get number of rings in the polygon
      numRings = ( int * )( mGeometry + 1 + sizeof( int ) );
      if ( !( *numRings ) )  // sanity check for zero rings in polygon
      {
        return QString();
      }
      int *ringStart; // index of first point for each ring
      int *ringNumPoints; // number of points in each ring
      ringStart = new int[*numRings];
      ringNumPoints = new int[*numRings];
      ptr = mGeometry + 1 + 2 * sizeof( int ); // set pointer to the first ring
      for ( idx = 0; idx < *numRings; idx++ )
      {
        if ( idx != 0 )
        {
          mWkt += ", ";
        }
        mWkt += "[ ";
        // get number of points in the ring
        nPoints = ( int * ) ptr;
        ringNumPoints[idx] = *nPoints;
        ptr += 4;

        for ( jdx = 0; jdx < *nPoints; jdx++ )
        {
          if ( jdx != 0 )
          {
            mWkt += ", ";
          }
          mWkt += "[";
          x = ( double * ) ptr;
          mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          mWkt += ", ";
          ptr += sizeof( double );
          y = ( double * ) ptr;
          mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          mWkt += "]";
        }
        mWkt += " ]";
      }
      mWkt += " ] }";
      delete [] ringStart;
      delete [] ringNumPoints;
      return mWkt;
    }

    case QGis::WKBMultiPoint25D:
      hasZValue = true;
    case QGis::WKBMultiPoint:
    {
      unsigned char *ptr;
      int idx;
      int *nPoints;

      mWkt += "{ \"type\": \"MultiPoint\", \"coordinates\": [ ";
      nPoints = ( int* )( mGeometry + 5 );
      ptr = mGeometry + 5 + sizeof( int );
      for ( idx = 0; idx < *nPoints; ++idx )
      {
        ptr += ( 1 + sizeof( int ) );
        if ( idx != 0 )
        {
          mWkt += ", ";
        }
        mWkt += "[";
        x = ( double * )( ptr );
        mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        mWkt += ", ";
        ptr += sizeof( double );
        y = ( double * )( ptr );
        mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
        ptr += sizeof( double );
        if ( hasZValue )
        {
          ptr += sizeof( double );
        }
        mWkt += "]";
      }
      mWkt += " ] }";
      return mWkt;
    }

    case QGis::WKBMultiLineString25D:
      hasZValue = true;
    case QGis::WKBMultiLineString:
    {
      QgsDebugMsg( "MULTILINESTRING found" );
      unsigned char *ptr;
      int idx, jdx, numLineStrings;
      int *nPoints;

      mWkt += "{ \"type\": \"MultiLineString\", \"coordinates\": [ ";
      numLineStrings = ( int )( mGeometry[5] );
      ptr = mGeometry + 9;
      for ( jdx = 0; jdx < numLineStrings; jdx++ )
      {
        if ( jdx != 0 )
        {
          mWkt += ", ";
        }
        mWkt += "[ ";
        ptr += 5; // skip type since we know its 2
        nPoints = ( int * ) ptr;
        ptr += sizeof( int );
        for ( idx = 0; idx < *nPoints; idx++ )
        {
          if ( idx != 0 )
          {
            mWkt += ", ";
          }
          mWkt += "[";
          x = ( double * ) ptr;
          mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          ptr += sizeof( double );
          mWkt += ", ";
          y = ( double * ) ptr;
          mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          mWkt += "]";
        }
        mWkt += " ]";
      }
      mWkt += " ] }";
      return mWkt;
    }

    case QGis::WKBMultiPolygon25D:
      hasZValue = true;
    case QGis::WKBMultiPolygon:
    {
      QgsDebugMsg( "MULTIPOLYGON found" );
      unsigned char *ptr;
      int idx, jdx, kdx;
      int *numPolygons, *numRings, *nPoints;

      mWkt += "{ \"type\": \"MultiPolygon\", \"coordinates\": [ ";
      ptr = mGeometry + 5;
      numPolygons = ( int * ) ptr;
      ptr = mGeometry + 9;
      for ( kdx = 0; kdx < *numPolygons; kdx++ )
      {
        if ( kdx != 0 )
        {
          mWkt += ", ";
        }
        mWkt += "[ ";
        ptr += 5;
        numRings = ( int * ) ptr;
        ptr += 4;
        for ( idx = 0; idx < *numRings; idx++ )
        {
          if ( idx != 0 )
          {
            mWkt += ", ";
          }
          mWkt += "[ ";
          nPoints = ( int * ) ptr;
          ptr += 4;
          for ( jdx = 0; jdx < *nPoints; jdx++ )
          {
            if ( jdx != 0 )
            {
              mWkt += ", ";
            }
            mWkt += "[";
            x = ( double * ) ptr;
            mWkt += QString::number( *x, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
            ptr += sizeof( double );
            mWkt += ", ";
            y = ( double * ) ptr;
            mWkt += QString::number( *y, 'f', 8 ).remove( QRegExp( "[0]{1,7}$" ) );
            ptr += sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
            mWkt += "]";
          }
          mWkt += " ]";
        }
        mWkt += " ]";
      }
      mWkt += " ] }";
      return mWkt;
    }

    default:
      QgsDebugMsg( "error: mGeometry type not recognized" );
      return QString::null;
  }
}


bool QgsGeometry::exportWkbToGeos()
{
  QgsDebugMsgLevel( "entered.", 3 );

  if ( !mDirtyGeos )
  {
    // No need to convert again
    return true;
  }

  if ( mGeos )
  {
    GEOSGeom_destroy( mGeos );
    mGeos = 0;
  }

  // this probably shouldn't return true
  if ( !mGeometry )
  {
    // no WKB => no GEOS
    mDirtyGeos = false;
    return true;
  }

  double *x;
  double *y;
  int *nPoints;
  int *numRings;
  int *numPolygons;
  int *numLineStrings;
  int idx, jdx, kdx;
  unsigned char *ptr;
  QgsPoint pt;
  QGis::WkbType wkbtype;
  bool hasZValue = false;

  //wkbtype = (mGeometry[0] == 1) ? mGeometry[1] : mGeometry[4];
  memcpy( &wkbtype, &( mGeometry[1] ), sizeof( int ) );

  try
  {
    switch ( wkbtype )
    {
      case QGis::WKBPoint25D:
      case QGis::WKBPoint:
      {
        x = ( double * )( mGeometry + 5 );
        y = ( double * )( mGeometry + 5 + sizeof( double ) );

        mGeos = createGeosPoint( QgsPoint( *x, *y ) );
        mDirtyGeos = false;
        break;
      }

      case QGis::WKBMultiPoint25D:
        hasZValue = true;
      case QGis::WKBMultiPoint:
      {
        QVector<GEOSGeometry *> points;

        ptr = mGeometry + 5;
        nPoints = ( int * ) ptr;
        ptr = mGeometry + 1 + 2 * sizeof( int );
        for ( idx = 0; idx < *nPoints; idx++ )
        {
          ptr += ( 1 + sizeof( int ) );
          x = ( double * ) ptr;
          ptr += sizeof( double );
          y = ( double * ) ptr;
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }
          points << createGeosPoint( QgsPoint( *x, *y ) );
        }
        mGeos = createGeosCollection( GEOS_MULTIPOINT, points );
        mDirtyGeos = false;
        break;
      }

      case QGis::WKBLineString25D:
        hasZValue = true;
      case QGis::WKBLineString:
      {
        QgsDebugMsgLevel( "Linestring found", 3 );

        QgsPolyline sequence;

        ptr = mGeometry + 5;
        nPoints = ( int * ) ptr;
        ptr = mGeometry + 1 + 2 * sizeof( int );
        for ( idx = 0; idx < *nPoints; idx++ )
        {
          x = ( double * ) ptr;
          ptr += sizeof( double );
          y = ( double * ) ptr;
          ptr += sizeof( double );
          if ( hasZValue )
          {
            ptr += sizeof( double );
          }

          sequence << QgsPoint( *x, *y );
        }
        mDirtyGeos = false;
        mGeos = createGeosLineString( sequence );
        break;
      }

      case QGis::WKBMultiLineString25D:
        hasZValue = true;
      case QGis::WKBMultiLineString:
      {
        QVector<GEOSGeometry*> lines;
        numLineStrings = ( int* )( mGeometry + 5 );
        ptr = ( mGeometry + 9 );
        for ( jdx = 0; jdx < *numLineStrings; jdx++ )
        {
          QgsPolyline sequence;

          // each of these is a wbklinestring so must handle as such
          ptr += 5;   // skip type since we know its 2
          nPoints = ( int * ) ptr;
          ptr += sizeof( int );
          for ( idx = 0; idx < *nPoints; idx++ )
          {
            x = ( double * ) ptr;
            ptr += sizeof( double );
            y = ( double * ) ptr;
            ptr += sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
            sequence << QgsPoint( *x, *y );
          }
          lines << createGeosLineString( sequence );
        }
        mGeos = createGeosCollection( GEOS_MULTILINESTRING, lines );
        mDirtyGeos = false;
        break;
      }

      case QGis::WKBPolygon25D:
        hasZValue = true;
      case QGis::WKBPolygon:
      {
        QgsDebugMsgLevel( "Polygon found", 3 );

        // get number of rings in the polygon
        numRings = ( int * )( mGeometry + 1 + sizeof( int ) );
        ptr = mGeometry + 1 + 2 * sizeof( int );

        QVector<GEOSGeometry*> rings;

        for ( idx = 0; idx < *numRings; idx++ )
        {
          //QgsDebugMsg("Ring nr: "+QString::number(idx));

          QgsPolyline sequence;

          // get number of points in the ring
          nPoints = ( int * ) ptr;
          ptr += 4;
          for ( jdx = 0; jdx < *nPoints; jdx++ )
          {
            // add points to a point array for drawing the polygon
            x = ( double * ) ptr;
            ptr += sizeof( double );
            y = ( double * ) ptr;
            ptr += sizeof( double );
            if ( hasZValue )
            {
              ptr += sizeof( double );
            }
            sequence << QgsPoint( *x, *y );
          }

          rings << createGeosLinearRing( sequence );
        }
        mGeos = createGeosPolygon( rings );
        mDirtyGeos = false;
        break;
      }

      case QGis::WKBMultiPolygon25D:
        hasZValue = true;
      case QGis::WKBMultiPolygon:
      {
        QgsDebugMsgLevel( "Multipolygon found", 3 );

        QVector<GEOSGeometry*> polygons;

        // get the number of polygons
        ptr = mGeometry + 5;
        numPolygons = ( int * ) ptr;
        ptr = mGeometry + 9;
        for ( kdx = 0; kdx < *numPolygons; kdx++ )
        {
          //QgsDebugMsg("Polygon nr: "+QString::number(kdx));
          QVector<GEOSGeometry*> rings;

          //skip the endian and mGeometry type info and
          // get number of rings in the polygon
          ptr += 5;
          numRings = ( int * ) ptr;
          ptr += 4;
          for ( idx = 0; idx < *numRings; idx++ )
          {
            //QgsDebugMsg("Ring nr: "+QString::number(idx));

            QgsPolyline sequence;

            // get number of points in the ring
            nPoints = ( int * ) ptr;
            ptr += 4;
            for ( jdx = 0; jdx < *nPoints; jdx++ )
            {
              // add points to a point array for drawing the polygon
              x = ( double * ) ptr;
              ptr += sizeof( double );
              y = ( double * ) ptr;
              ptr += sizeof( double );
              if ( hasZValue )
              {
                ptr += sizeof( double );
              }
              sequence << QgsPoint( *x, *y );
            }

            rings << createGeosLinearRing( sequence );
          }

          polygons << createGeosPolygon( rings );
        }
        mGeos = createGeosCollection( GEOS_MULTIPOLYGON, polygons );
        mDirtyGeos = false;
        break;
      }

      default:
        return false;
    }
  }
  CATCH_GEOS( false )

  return true;
}

bool QgsGeometry::exportGeosToWkb()
{
  //QgsDebugMsg("entered.");
  if ( !mDirtyWkb )
  {
    // No need to convert again
    return true;
  }

  // clear the WKB, ready to replace with the new one
  if ( mGeometry )
  {
    delete [] mGeometry;
    mGeometry = 0;
  }

  if ( !mGeos )
  {
    // GEOS is null, therefore WKB is null.
    mDirtyWkb = false;
    return true;
  }

  // set up byteOrder
  char byteOrder = QgsApplication::endian();

  switch ( GEOSGeomTypeId( mGeos ) )
  {
    case GEOS_POINT:                 // a point
    {
      mGeometrySize = 1 +   // sizeof(byte)
                      4 +   // sizeof(uint32)
                      2 * sizeof( double );
      mGeometry = new unsigned char[mGeometrySize];

      // assign byteOrder
      memcpy( mGeometry, &byteOrder, 1 );

      // assign wkbType
      int wkbType = QGis::WKBPoint;
      memcpy( mGeometry + 1, &wkbType, 4 );

      const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( mGeos );

      double x, y;
      GEOSCoordSeq_getX( cs, 0, &x );
      GEOSCoordSeq_getY( cs, 0, &y );

      memcpy( mGeometry + 5, &x, sizeof( double ) );
      memcpy( mGeometry + 13, &y, sizeof( double ) );

      mDirtyWkb = false;
      return true;
    } // case GEOS_GEOM::GEOS_POINT

    case GEOS_LINESTRING:            // a linestring
    {
      //QgsDebugMsg("Got a geos::GEOS_LINESTRING.");

      const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( mGeos );
      unsigned int numPoints;
      GEOSCoordSeq_getSize( cs, &numPoints );

      // allocate some space for the WKB
      mGeometrySize = 1 +   // sizeof(byte)
                      4 +   // sizeof(uint32)
                      4 +   // sizeof(uint32)
                      (( sizeof( double ) +
                         sizeof( double ) ) * numPoints );

      mGeometry = new unsigned char[mGeometrySize];

      unsigned char* ptr = mGeometry;

      // assign byteOrder
      memcpy( ptr, &byteOrder, 1 );
      ptr += 1;

      // assign wkbType
      int wkbType = QGis::WKBLineString;
      memcpy( ptr, &wkbType, 4 );
      ptr += 4;

      // assign numPoints
      memcpy( ptr, &numPoints, 4 );
      ptr += 4;

      const GEOSCoordSequence *sequence = GEOSGeom_getCoordSeq( mGeos );

      // assign points
      for ( unsigned int n = 0; n < numPoints; n++ )
      {
        // assign x
        GEOSCoordSeq_getX( sequence, n, ( double * )ptr );
        ptr += sizeof( double );

        // assign y
        GEOSCoordSeq_getY( sequence, n, ( double * )ptr );
        ptr += sizeof( double );
      }

      mDirtyWkb = false;
      return true;

      // TODO: Deal with endian-ness
    } // case GEOS_GEOM::GEOS_LINESTRING

    case GEOS_LINEARRING:            // a linear ring (linestring with 1st point == last point)
    {
      // TODO
      break;
    } // case GEOS_GEOM::GEOS_LINEARRING

    case GEOS_POLYGON:               // a polygon
    {
      int geometrySize;
      unsigned int nPointsInRing = 0;

      //first calculate the geometry size
      geometrySize = 1 + 2 * sizeof( int ); //endian, type, number of rings
      const GEOSGeometry *theRing = GEOSGetExteriorRing( mGeos );
      if ( theRing )
      {
        geometrySize += sizeof( int );
        geometrySize += getNumGeosPoints( theRing ) * 2 * sizeof( double );
      }
      for ( int i = 0; i < GEOSGetNumInteriorRings( mGeos ); ++i )
      {
        geometrySize += sizeof( int ); //number of points in ring
        theRing = GEOSGetInteriorRingN( mGeos, i );
        if ( theRing )
        {
          geometrySize += getNumGeosPoints( theRing ) * 2 * sizeof( double );
        }
      }

      mGeometry = new unsigned char[geometrySize];
      mGeometrySize = geometrySize;

      //then fill the geometry itself into the wkb
      int position = 0;
      // assign byteOrder
      memcpy( mGeometry, &byteOrder, 1 );
      position += 1;
      int wkbtype = QGis::WKBPolygon;
      memcpy( &mGeometry[position], &wkbtype, sizeof( int ) );
      position += sizeof( int );
      int nRings = GEOSGetNumInteriorRings( mGeos ) + 1;
      memcpy( &mGeometry[position], &nRings, sizeof( int ) );
      position += sizeof( int );

      //exterior ring first
      theRing = GEOSGetExteriorRing( mGeos );
      if ( theRing )
      {
        nPointsInRing = getNumGeosPoints( theRing );
        memcpy( &mGeometry[position], &nPointsInRing, sizeof( int ) );
        position += sizeof( int );

        const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( theRing );
        unsigned int n;
        GEOSCoordSeq_getSize( cs, &n );

        for ( unsigned int j = 0; j < n; ++j )
        {
          GEOSCoordSeq_getX( cs, j, ( double * )&mGeometry[position] );
          position += sizeof( double );
          GEOSCoordSeq_getY( cs, j, ( double * )&mGeometry[position] );
          position += sizeof( double );
        }
      }

      //interior rings after
      for ( int i = 0; i < GEOSGetNumInteriorRings( mGeos ); i++ )
      {
        theRing = GEOSGetInteriorRingN( mGeos, i );

        const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( theRing );
        GEOSCoordSeq_getSize( cs, &nPointsInRing );

        memcpy( &mGeometry[position], &nPointsInRing, sizeof( int ) );
        position += sizeof( int );

        for ( unsigned int j = 0; j < nPointsInRing; j++ )
        {
          GEOSCoordSeq_getX( cs, j, ( double * )&mGeometry[position] );
          position += sizeof( double );
          GEOSCoordSeq_getY( cs, j, ( double * )&mGeometry[position] );
          position += sizeof( double );
        }
      }
      mDirtyWkb = false;
      return true;
    } // case GEOS_GEOM::GEOS_POLYGON
    break;

    case GEOS_MULTIPOINT:            // a collection of points
    {
      // determine size of geometry
      int geometrySize = 1 + 2 * sizeof( int );
      for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); i++ )
      {
        geometrySize += 1 + sizeof( int ) + 2 * sizeof( double );
      }

      mGeometry = new unsigned char[geometrySize];
      mGeometrySize = geometrySize;
      int wkbPosition = 0; //current position in the byte array

      memcpy( mGeometry, &byteOrder, 1 );
      wkbPosition += 1;
      int wkbtype = QGis::WKBMultiPoint;
      memcpy( &mGeometry[wkbPosition], &wkbtype, sizeof( int ) );
      wkbPosition += sizeof( int );
      int numPoints = GEOSGetNumGeometries( mGeos );
      memcpy( &mGeometry[wkbPosition], &numPoints, sizeof( int ) );
      wkbPosition += sizeof( int );

      int pointType = QGis::WKBPoint;
      const GEOSGeometry *currentPoint = 0;

      for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); i++ )
      {
        //copy endian and point type
        memcpy( &mGeometry[wkbPosition], &byteOrder, 1 );
        wkbPosition += 1;
        memcpy( &mGeometry[wkbPosition], &pointType, sizeof( int ) );
        wkbPosition += sizeof( int );

        currentPoint = GEOSGetGeometryN( mGeos, i );

        const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( currentPoint );

        GEOSCoordSeq_getX( cs, 0, ( double* )&mGeometry[wkbPosition] );
        wkbPosition += sizeof( double );
        GEOSCoordSeq_getY( cs, 0, ( double* )&mGeometry[wkbPosition] );
        wkbPosition += sizeof( double );
      }
      mDirtyWkb = false;
      return true;
    } // case GEOS_GEOM::GEOS_MULTIPOINT

    case GEOS_MULTILINESTRING:       // a collection of linestrings
    {
      // determine size of geometry
      int geometrySize = 1 + 2 * sizeof( int );
      for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); i++ )
      {
        geometrySize += 1 + 2 * sizeof( int );
        geometrySize += getNumGeosPoints( GEOSGetGeometryN( mGeos, i ) ) * 2 * sizeof( double );
      }

      mGeometry = new unsigned char[geometrySize];
      mGeometrySize = geometrySize;
      int wkbPosition = 0; //current position in the byte array

      memcpy( mGeometry, &byteOrder, 1 );
      wkbPosition += 1;
      int wkbtype = QGis::WKBMultiLineString;
      memcpy( &mGeometry[wkbPosition], &wkbtype, sizeof( int ) );
      wkbPosition += sizeof( int );
      int numLines = GEOSGetNumGeometries( mGeos );
      memcpy( &mGeometry[wkbPosition], &numLines, sizeof( int ) );
      wkbPosition += sizeof( int );

      //loop over lines
      int lineType = QGis::WKBLineString;
      const GEOSCoordSequence *cs = 0;
      unsigned int lineSize;

      for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); i++ )
      {
        //endian and type WKBLineString
        memcpy( &mGeometry[wkbPosition], &byteOrder, 1 );
        wkbPosition += 1;
        memcpy( &mGeometry[wkbPosition], &lineType, sizeof( int ) );
        wkbPosition += sizeof( int );

        cs = GEOSGeom_getCoordSeq( GEOSGetGeometryN( mGeos, i ) );

        //line size
        GEOSCoordSeq_getSize( cs, &lineSize );
        memcpy( &mGeometry[wkbPosition], &lineSize, sizeof( int ) );
        wkbPosition += sizeof( int );

        //vertex coordinates
        for ( unsigned int j = 0; j < lineSize; ++j )
        {
          GEOSCoordSeq_getX( cs, j, ( double* )&mGeometry[wkbPosition] );
          wkbPosition += sizeof( double );
          GEOSCoordSeq_getY( cs, j, ( double* )&mGeometry[wkbPosition] );
          wkbPosition += sizeof( double );
        }
      }
      mDirtyWkb = false;
      return true;
    } // case GEOS_GEOM::GEOS_MULTILINESTRING

    case GEOS_MULTIPOLYGON:          // a collection of polygons
    {
      //first determine size of geometry
      int geometrySize = 1 + ( 2 * sizeof( int ) ); //endian, type, number of polygons
      for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); i++ )
      {
        const GEOSGeometry *thePoly = GEOSGetGeometryN( mGeos, i );
        geometrySize += 1 + 2 * sizeof( int ); //endian, type, number of rings
        //exterior ring
        geometrySize += sizeof( int ); //number of points in exterior ring
        const GEOSGeometry *exRing = GEOSGetExteriorRing( thePoly );
        geometrySize += 2 * sizeof( double ) * getNumGeosPoints( exRing );

        const GEOSGeometry *intRing = 0;
        for ( int j = 0; j < GEOSGetNumInteriorRings( thePoly ); j++ )
        {
          geometrySize += sizeof( int ); //number of points in ring
          intRing = GEOSGetInteriorRingN( thePoly, j );
          geometrySize += 2 * sizeof( double ) * getNumGeosPoints( intRing );
        }
      }

      mGeometry = new unsigned char[geometrySize];
      mGeometrySize = geometrySize;
      int wkbPosition = 0; //current position in the byte array

      memcpy( mGeometry, &byteOrder, 1 );
      wkbPosition += 1;
      int wkbtype = QGis::WKBMultiPolygon;
      memcpy( &mGeometry[wkbPosition], &wkbtype, sizeof( int ) );
      wkbPosition += sizeof( int );
      int numPolygons = GEOSGetNumGeometries( mGeos );
      memcpy( &mGeometry[wkbPosition], &numPolygons, sizeof( int ) );
      wkbPosition += sizeof( int );

      //loop over polygons
      for ( int i = 0; i < GEOSGetNumGeometries( mGeos ); i++ )
      {
        const GEOSGeometry *thePoly = GEOSGetGeometryN( mGeos, i );
        memcpy( &mGeometry[wkbPosition], &byteOrder, 1 );
        wkbPosition += 1;
        int polygonType = QGis::WKBPolygon;
        memcpy( &mGeometry[wkbPosition], &polygonType, sizeof( int ) );
        wkbPosition += sizeof( int );
        int numRings = GEOSGetNumInteriorRings( thePoly ) + 1;
        memcpy( &mGeometry[wkbPosition], &numRings, sizeof( int ) );
        wkbPosition += sizeof( int );

        //exterior ring
        const GEOSGeometry *theRing = GEOSGetExteriorRing( thePoly );
        int nPointsInRing = getNumGeosPoints( theRing );
        memcpy( &mGeometry[wkbPosition], &nPointsInRing, sizeof( int ) );
        wkbPosition += sizeof( int );
        const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( theRing );

        for ( int k = 0; k < nPointsInRing; ++k )
        {
          GEOSCoordSeq_getX( cs, k, ( double * )&mGeometry[wkbPosition] );
          wkbPosition += sizeof( double );
          GEOSCoordSeq_getY( cs, k, ( double * )&mGeometry[wkbPosition] );
          wkbPosition += sizeof( double );
        }

        //interior rings
        for ( int j = 0; j < GEOSGetNumInteriorRings( thePoly ); j++ )
        {
          theRing = GEOSGetInteriorRingN( thePoly, j );
          nPointsInRing = getNumGeosPoints( theRing );
          memcpy( &mGeometry[wkbPosition], &nPointsInRing, sizeof( int ) );
          wkbPosition += sizeof( int );
          const GEOSCoordSequence *cs = GEOSGeom_getCoordSeq( theRing );

          for ( int k = 0; k < nPointsInRing; ++k )
          {
            GEOSCoordSeq_getX( cs, k, ( double * )&mGeometry[wkbPosition] );
            wkbPosition += sizeof( double );
            GEOSCoordSeq_getY( cs, k, ( double * )&mGeometry[wkbPosition] );
            wkbPosition += sizeof( double );
          }
        }
      }
      mDirtyWkb = false;
      return true;
    } // case GEOS_GEOM::GEOS_MULTIPOLYGON

    case GEOS_GEOMETRYCOLLECTION:    // a collection of heterogeneus geometries
    {
      // TODO
      QgsDebugMsg( "geometry collection - not supported" );
      break;
    } // case GEOS_GEOM::GEOS_GEOMETRYCOLLECTION

  } // switch (mGeos->getGeometryTypeId())

  return false;
}

bool QgsGeometry::convertToMultiType()
{
  if ( !mGeometry )
  {
    return false;
  }

  QGis::WkbType geomType = wkbType();

  if ( geomType == QGis::WKBMultiPoint || geomType == QGis::WKBMultiPoint25D ||
       geomType == QGis::WKBMultiLineString || geomType == QGis::WKBMultiLineString25D ||
       geomType == QGis::WKBMultiPolygon || geomType == QGis::WKBMultiPolygon25D || geomType == QGis::WKBUnknown )
  {
    return false; //no need to convert
  }

  int newGeomSize = mGeometrySize + 1 + 2 * sizeof( int ); //endian: 1, multitype: sizeof(int), number of geometries: sizeof(int)
  unsigned char* newGeometry = new unsigned char[newGeomSize];

  int currentWkbPosition = 0;
  //copy endian
  char byteOrder = QgsApplication::endian();
  memcpy( &newGeometry[currentWkbPosition], &byteOrder, 1 );
  currentWkbPosition += 1;

  //copy wkbtype
  //todo
  QGis::WkbType newMultiType;
  switch ( geomType )
  {
    case QGis::WKBPoint:
      newMultiType = QGis::WKBMultiPoint;
      break;
    case QGis::WKBPoint25D:
      newMultiType = QGis::WKBMultiPoint25D;
      break;
    case QGis::WKBLineString:
      newMultiType = QGis::WKBMultiLineString;
      break;
    case QGis::WKBLineString25D:
      newMultiType = QGis::WKBMultiLineString25D;
      break;
    case QGis::WKBPolygon:
      newMultiType = QGis::WKBMultiPolygon;
      break;
    case QGis::WKBPolygon25D:
      newMultiType = QGis::WKBMultiPolygon25D;
      break;
    default:
      delete newGeometry;
      return false;
  }
  memcpy( &newGeometry[currentWkbPosition], &newMultiType, sizeof( int ) );
  currentWkbPosition += sizeof( int );

  //copy number of geometries
  int nGeometries = 1;
  memcpy( &newGeometry[currentWkbPosition], &nGeometries, sizeof( int ) );
  currentWkbPosition += sizeof( int );

  //copy the existing single geometry
  memcpy( &newGeometry[currentWkbPosition], mGeometry, mGeometrySize );

  delete [] mGeometry;
  mGeometry = newGeometry;
  mGeometrySize = newGeomSize;
  mDirtyGeos = true;
  return true;
}

void QgsGeometry::translateVertex( int& wkbPosition, double dx, double dy, bool hasZValue )
{
  double x, y, translated_x, translated_y;

  //x-coordinate
  x = *(( double * )( &( mGeometry[wkbPosition] ) ) );
  translated_x = x + dx;
  memcpy( &( mGeometry[wkbPosition] ), &translated_x, sizeof( double ) );
  wkbPosition += sizeof( double );

  //y-coordinate
  y = *(( double * )( &( mGeometry[wkbPosition] ) ) );
  translated_y = y + dy;
  memcpy( &( mGeometry[wkbPosition] ), &translated_y, sizeof( double ) );
  wkbPosition += sizeof( double );

  if ( hasZValue )
  {
    wkbPosition += sizeof( double );
  }
}

void QgsGeometry::transformVertex( int& wkbPosition, const QgsCoordinateTransform& ct, bool hasZValue )
{
  double x, y, z;


  x = *(( double * )( &( mGeometry[wkbPosition] ) ) );
  y = *(( double * )( &( mGeometry[wkbPosition + sizeof( double )] ) ) );
  z = 0.0; // Ignore Z for now.

  ct.transformInPlace( x, y, z );

  // new x-coordinate
  memcpy( &( mGeometry[wkbPosition] ), &x, sizeof( double ) );
  wkbPosition += sizeof( double );

  // new y-coordinate
  memcpy( &( mGeometry[wkbPosition] ), &y, sizeof( double ) );
  wkbPosition += sizeof( double );

  if ( hasZValue )
  {
    wkbPosition += sizeof( double );
  }
}

int QgsGeometry::splitLinearGeometry( GEOSGeometry *splitLine, QList<QgsGeometry*>& newGeometries )
{
  if ( !splitLine )
  {
    return 2;
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 5;
  }

  //first test if linestring intersects geometry. If not, return straight away
  if ( !GEOSIntersects( splitLine, mGeos ) )
  {
    return 1;
  }

  //check that split line has no linear intersection
  int linearIntersect = GEOSRelatePattern( mGeos, splitLine, "1********" );
  if ( linearIntersect > 0 )
  {
    return 3;
  }

  GEOSGeometry* splitGeom = GEOSDifference( mGeos, splitLine );
  QVector<GEOSGeometry*> lineGeoms;

  int splitType = GEOSGeomTypeId( splitGeom );
  if ( splitType == GEOS_MULTILINESTRING )
  {
    int nGeoms = GEOSGetNumGeometries( splitGeom );
    for ( int i = 0; i < nGeoms; ++i )
    {
      lineGeoms << GEOSGeom_clone( GEOSGetGeometryN( splitGeom, i ) );
    }
  }
  else
  {
    lineGeoms << GEOSGeom_clone( splitGeom );
  }

  mergeGeometriesMultiTypeSplit( lineGeoms );

  if ( lineGeoms.size() > 0 )
  {
    GEOSGeom_destroy( mGeos );
    mGeos = lineGeoms[0];
    mDirtyWkb = true;
  }

  for ( int i = 1; i < lineGeoms.size(); ++i )
  {
    newGeometries << fromGeosGeom( lineGeoms[i] );
  }

  GEOSGeom_destroy( splitGeom );
  return 0;
}

int QgsGeometry::splitPolygonGeometry( GEOSGeometry* splitLine, QList<QgsGeometry*>& newGeometries )
{
  if ( !splitLine )
  {
    return 2;
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 5;
  }

  //first test if linestring intersects geometry. If not, return straight away
  if ( !GEOSIntersects( splitLine, mGeos ) )
  {
    return 1;
  }

  //first union all the polygon rings together (to get them noded, see JTS developer guide)
  GEOSGeometry *nodedGeometry = nodeGeometries( splitLine, mGeos );
  if ( !nodedGeometry )
  {
    return 2; //an error occured during noding
  }

#if defined(GEOS_VERSION_MAJOR) && defined(GEOS_VERSION_MINOR) && \
    ((GEOS_VERSION_MAJOR>3) || ((GEOS_VERSION_MAJOR==3) && (GEOS_VERSION_MINOR>=1)))
  GEOSGeometry *cutEdges = GEOSPolygonizer_getCutEdges( &nodedGeometry, 1 );
  if ( cutEdges )
  {
    if ( numberOfGeometries( cutEdges ) > 0 )
    {
      GEOSGeom_destroy( cutEdges );
      GEOSGeom_destroy( nodedGeometry );
      return 3;
    }

    GEOSGeom_destroy( cutEdges );
  }
#endif

  GEOSGeometry *polygons = GEOSPolygonize( &nodedGeometry, 1 );
  if ( !polygons || numberOfGeometries( polygons ) == 0 )
  {
    if ( polygons )
      GEOSGeom_destroy( polygons );

    GEOSGeom_destroy( nodedGeometry );

    return 4;
  }

  GEOSGeom_destroy( nodedGeometry );

  //test every polygon if contained in original geometry
  //include in result if yes
  QVector<GEOSGeometry*> testedGeometries;
  GEOSGeometry *intersectGeometry = 0;

  //ratio intersect geometry / geometry. This should be close to 1
  //if the polygon belongs to the input geometry

  for ( int i = 0; i < numberOfGeometries( polygons ); i++ )
  {
    const GEOSGeometry *polygon = GEOSGetGeometryN( polygons, i );
    intersectGeometry = GEOSIntersection( mGeos, polygon );
    if ( !intersectGeometry )
    {
      QgsDebugMsg( "intersectGeometry is NULL" );
      continue;
    }

    double intersectionArea;
    GEOSArea( intersectGeometry, &intersectionArea );

    double polygonArea;
    GEOSArea( polygon, &polygonArea );

    const double areaRatio = intersectionArea / polygonArea;
    if ( areaRatio > 0.99 && areaRatio < 1.01 )
      testedGeometries << GEOSGeom_clone( polygon );

    GEOSGeom_destroy( intersectGeometry );
  }

  bool splitDone = true;
  int nGeometriesThis = numberOfGeometries( mGeos ); //original number of geometries
  if ( testedGeometries.size() == nGeometriesThis )
  {
    splitDone = false;
  }

  mergeGeometriesMultiTypeSplit( testedGeometries );

  //no split done, preserve original geometry
  if ( !splitDone )
  {
    for ( int i = 0; i < testedGeometries.size(); ++i )
    {
      GEOSGeom_destroy( testedGeometries[i] );
    }
    return 1;
  }
  else if ( testedGeometries.size() > 0 ) //split successfull
  {
    GEOSGeom_destroy( mGeos );
    mGeos = testedGeometries[0];
    mDirtyWkb = true;
  }

  for ( int i = 1; i < testedGeometries.size(); ++i )
  {
    newGeometries << fromGeosGeom( testedGeometries[i] );
  }

  GEOSGeom_destroy( polygons );
  return 0;
}

GEOSGeometry* QgsGeometry::reshapePolygon( const GEOSGeometry* polygon, const GEOSGeometry* reshapeLineGeos )
{
  //go through outer shell and all inner rings and check if there is exactly one intersection of a ring and the reshape line
  int nIntersections = 0;
  int lastIntersectingRing = -2;
  const GEOSGeometry* lastIntersectingGeom = 0;

  int nRings = GEOSGetNumInteriorRings( polygon );
  if ( nRings < 0 )
  {
    return 0;
  }

  //does outer ring intersect?
  const GEOSGeometry* outerRing = GEOSGetExteriorRing( polygon );
  if ( GEOSIntersects( outerRing, reshapeLineGeos ) == 1 )
  {
    ++nIntersections;
    lastIntersectingRing = -1;
    lastIntersectingGeom = outerRing;
  }

  //do inner rings intersect?
  const GEOSGeometry **innerRings = new const GEOSGeometry*[nRings];

  try
  {
    for ( int i = 0; i < nRings; ++i )
    {
      innerRings[i] = GEOSGetInteriorRingN( polygon, i );
      if ( GEOSIntersects( innerRings[i], reshapeLineGeos ) == 1 )
      {
        ++nIntersections;
        lastIntersectingRing = i;
        lastIntersectingGeom = innerRings[i];
      }
    }
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    nIntersections = 0;
  }

  if ( nIntersections != 1 ) //reshape line is only allowed to intersect one ring
  {
    delete [] innerRings;
    return 0;
  }

  //we have one intersecting ring, let's try to reshape it
  GEOSGeometry* reshapeResult = reshapeLine( lastIntersectingGeom, reshapeLineGeos );
  if ( !reshapeResult )
  {
    delete [] innerRings;
    return 0;
  }

  //if reshaping took place, we need to reassemble the polygon and its rings
  GEOSGeometry* newRing = 0;
  const GEOSCoordSequence* reshapeSequence = GEOSGeom_getCoordSeq( reshapeResult );
  GEOSCoordSequence* newCoordSequence = GEOSCoordSeq_clone( reshapeSequence );

  GEOSGeom_destroy( reshapeResult );

  newRing = GEOSGeom_createLinearRing( newCoordSequence );
  if ( !newRing )
  {
    delete [] innerRings;
    return 0;
  }


  GEOSGeometry* newOuterRing = 0;
  if ( lastIntersectingRing == -1 )
  {
    newOuterRing = newRing;
  }
  else
  {
    newOuterRing = GEOSGeom_clone( outerRing );
  }

  //check if all the rings are still inside the outer boundary
  QList<GEOSGeometry*> ringList;
  if ( nRings > 0 )
  {
    GEOSGeometry* outerRingPoly = GEOSGeom_createPolygon( GEOSGeom_clone( newOuterRing ), 0, 0 );
    if ( outerRingPoly )
    {
      GEOSGeometry* currentRing = 0;
      for ( int i = 0; i < nRings; ++i )
      {
        if ( lastIntersectingRing == i )
        {
          currentRing = newRing;
        }
        else
        {
          currentRing = GEOSGeom_clone( innerRings[i] );
        }

        //possibly a ring is no longer contained in the result polygon after reshape
        if ( GEOSContains( outerRingPoly, currentRing ) == 1 )
        {
          ringList.push_back( currentRing );
        }
        else
        {
          GEOSGeom_destroy( currentRing );
        }
      }
    }
    GEOSGeom_destroy( outerRingPoly );
  }

  GEOSGeometry** newInnerRings = new GEOSGeometry*[ringList.size()];
  for ( int i = 0; i < ringList.size(); ++i )
  {
    newInnerRings[i] = ringList.at( i );
  }

  delete [] innerRings;

  GEOSGeometry* reshapedPolygon = GEOSGeom_createPolygon( newOuterRing, newInnerRings, ringList.size() );
  delete[] newInnerRings;
  if ( !reshapedPolygon )
  {
    return 0;
  }
  return reshapedPolygon;
}

GEOSGeometry* QgsGeometry::reshapeLine( const GEOSGeometry* line, const GEOSGeometry* reshapeLineGeos )
{
  if ( !line || !reshapeLineGeos )
  {
    return 0;
  }

  bool atLeastTwoIntersections = false;

  try
  {
    //make sure there are at least two intersection between line and reshape geometry
    GEOSGeometry* intersectGeom = GEOSIntersection( line, reshapeLineGeos );
    if ( intersectGeom )
    {
      atLeastTwoIntersections = ( GEOSGeomTypeId( intersectGeom ) == GEOS_MULTIPOINT && GEOSGetNumGeometries( intersectGeom ) > 1 );
      GEOSGeom_destroy( intersectGeom );
    }
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    atLeastTwoIntersections = false;
  }

  if ( !atLeastTwoIntersections )
  {
    return 0;
  }

  //begin and end point of original line
  const GEOSCoordSequence* lineCoordSeq = GEOSGeom_getCoordSeq( line );
  if ( !lineCoordSeq )
  {
    return 0;
  }
  unsigned int lineCoordSeqSize;
  if ( GEOSCoordSeq_getSize( lineCoordSeq, &lineCoordSeqSize ) == 0 )
  {
    return 0;
  }
  if ( lineCoordSeqSize < 2 )
  {
    return 0;
  }
  //first and last vertex of line
  double x1, y1, x2, y2;
  GEOSCoordSeq_getX( lineCoordSeq, 0, &x1 );
  GEOSCoordSeq_getY( lineCoordSeq, 0, &y1 );
  GEOSCoordSeq_getX( lineCoordSeq, lineCoordSeqSize - 1, &x2 );
  GEOSCoordSeq_getY( lineCoordSeq, lineCoordSeqSize - 1, &y2 );
  GEOSGeometry* beginLineVertex = createGeosPoint( QgsPoint( x1, y1 ) );
  GEOSGeometry* endLineVertex = createGeosPoint( QgsPoint( x2, y2 ) );

  bool isRing = false;
  if ( GEOSGeomTypeId( line ) == GEOS_LINEARRING || GEOSEquals( beginLineVertex, endLineVertex ) == 1 )
  {
    isRing = true;
  }

//node line and reshape line
  GEOSGeometry* nodedGeometry = nodeGeometries( reshapeLineGeos, line );
  if ( !nodedGeometry )
  {
    GEOSGeom_destroy( beginLineVertex );
    GEOSGeom_destroy( endLineVertex );
    return 0;
  }

  //and merge them together
  GEOSGeometry *mergedLines = GEOSLineMerge( nodedGeometry );
  GEOSGeom_destroy( nodedGeometry );
  if ( !mergedLines )
  {
    GEOSGeom_destroy( beginLineVertex );
    GEOSGeom_destroy( endLineVertex );
    return 0;
  }

  int numMergedLines = GEOSGetNumGeometries( mergedLines );
  if ( numMergedLines < 2 ) //some special cases. Normally it is >2
  {
    GEOSGeom_destroy( beginLineVertex );
    GEOSGeom_destroy( endLineVertex );
    if ( numMergedLines == 1 ) //reshape line is from begin to endpoint. So we keep the reshapeline
    {
      return GEOSGeom_clone( reshapeLineGeos );
    }
    else
    {
      return 0;
    }
  }

  QList<GEOSGeometry*> resultLineParts; //collection with the line segments that will be contained in result
  QList<GEOSGeometry*> probableParts; //parts where we can decide on inclusion only after going through all the candidates

  for ( int i = 0; i < numMergedLines; ++i )
  {
    const GEOSGeometry* currentGeom;

    currentGeom = GEOSGetGeometryN( mergedLines, i );
    const GEOSCoordSequence* currentCoordSeq = GEOSGeom_getCoordSeq( currentGeom );
    unsigned int currentCoordSeqSize;
    GEOSCoordSeq_getSize( currentCoordSeq, &currentCoordSeqSize );
    if ( currentCoordSeqSize < 2 )
    {
      continue;
    }

    //get the two endpoints of the current line merge result
    double xBegin, xEnd, yBegin, yEnd;
    GEOSCoordSeq_getX( currentCoordSeq, 0, &xBegin );
    GEOSCoordSeq_getY( currentCoordSeq, 0, &yBegin );
    GEOSCoordSeq_getX( currentCoordSeq, currentCoordSeqSize - 1, &xEnd );
    GEOSCoordSeq_getY( currentCoordSeq, currentCoordSeqSize - 1, &yEnd );
    GEOSGeometry* beginCurrentGeomVertex = createGeosPoint( QgsPoint( xBegin, yBegin ) );
    GEOSGeometry* endCurrentGeomVertex = createGeosPoint( QgsPoint( xEnd, yEnd ) );

    //check how many endpoints of the line merge result are on the (original) line
    int nEndpointsOnOriginalLine = 0;
    if ( pointContainedInLine( beginCurrentGeomVertex, line ) == 1 )
    {
      nEndpointsOnOriginalLine += 1;
    }

    if ( pointContainedInLine( endCurrentGeomVertex, line ) == 1 )
    {
      nEndpointsOnOriginalLine += 1;
    }

    //check how many endpoints equal the endpoints of the original line
    int nEndpointsSameAsOriginalLine = 0;
    if ( GEOSEquals( beginCurrentGeomVertex, beginLineVertex ) == 1 || GEOSEquals( beginCurrentGeomVertex, endLineVertex ) == 1 )
    {
      nEndpointsSameAsOriginalLine += 1;
    }
    if ( GEOSEquals( endCurrentGeomVertex, beginLineVertex ) == 1 || GEOSEquals( endCurrentGeomVertex, endLineVertex ) == 1 )
    {
      nEndpointsSameAsOriginalLine += 1;
    }

    //check if the current geometry overlaps the original geometry (GEOSOverlap does not seem to work with linestrings)
    bool currentGeomOverlapsOriginalGeom = false;
    bool currentGeomOverlapsReshapeLine = false;
    if ( QgsGeometry::lineContainedInLine( currentGeom, line ) == 1 )
    {
      currentGeomOverlapsOriginalGeom = true;
    }
    if ( QgsGeometry::lineContainedInLine( currentGeom, reshapeLineGeos ) == 1 )
    {
      currentGeomOverlapsReshapeLine = true;
    }


    //logic to decide if this part belongs to the result
    if ( nEndpointsSameAsOriginalLine == 1 && nEndpointsOnOriginalLine == 2 && currentGeomOverlapsOriginalGeom )
    {
      resultLineParts.push_back( GEOSGeom_clone( currentGeom ) );
    }
    //for closed rings, we take one segment from the candidate list
    else if ( isRing && nEndpointsOnOriginalLine == 2 && currentGeomOverlapsOriginalGeom )
    {
      probableParts.push_back( GEOSGeom_clone( currentGeom ) );
    }
    else if ( nEndpointsOnOriginalLine == 2 && !currentGeomOverlapsOriginalGeom )
    {
      resultLineParts.push_back( GEOSGeom_clone( currentGeom ) );
    }
    else if ( nEndpointsSameAsOriginalLine == 2 && !currentGeomOverlapsOriginalGeom )
    {
      resultLineParts.push_back( GEOSGeom_clone( currentGeom ) );
    }
    else if ( currentGeomOverlapsOriginalGeom && currentGeomOverlapsReshapeLine )
    {
      resultLineParts.push_back( GEOSGeom_clone( currentGeom ) );
    }

    GEOSGeom_destroy( beginCurrentGeomVertex );
    GEOSGeom_destroy( endCurrentGeomVertex );
  }

  //add the longest segment from the probable list for rings (only used for polygon rings)
  if ( isRing && probableParts.size() > 0 )
  {
    GEOSGeometry* maxGeom = 0; //the longest geometry in the probabla list
    GEOSGeometry* currentGeom = 0;
    double maxLength = -DBL_MAX;
    double currentLength = 0;
    for ( int i = 0; i < probableParts.size(); ++i )
    {
      currentGeom = probableParts.at( i );
      GEOSLength( currentGeom, &currentLength );
      if ( currentLength > maxLength )
      {
        maxLength = currentLength;
        GEOSGeom_destroy( maxGeom );
        maxGeom = currentGeom;
      }
      else
      {
        GEOSGeom_destroy( currentGeom );
      }
    }
    resultLineParts.push_back( maxGeom );
  }

  GEOSGeom_destroy( beginLineVertex );
  GEOSGeom_destroy( endLineVertex );
  GEOSGeom_destroy( mergedLines );

  GEOSGeometry* result = 0;
  if ( resultLineParts.size() < 1 )
  {
    return 0;
  }
  if ( resultLineParts.size() == 1 ) //the whole result was reshaped
  {
    result = resultLineParts[0];
  }
  else //>1
  {
    GEOSGeometry **lineArray = new GEOSGeometry*[resultLineParts.size()];
    for ( int i = 0; i < resultLineParts.size(); ++i )
    {
      lineArray[i] = resultLineParts[i];
    }

    //create multiline from resultLineParts
    GEOSGeometry* multiLineGeom = GEOSGeom_createCollection( GEOS_MULTILINESTRING, lineArray, resultLineParts.size() );
    delete [] lineArray;

    //then do a linemerge with the newly combined partstrings
    result = GEOSLineMerge( multiLineGeom );
    GEOSGeom_destroy( multiLineGeom );
  }

  //now test if the result is a linestring. Otherwise something went wrong
  if ( GEOSGeomTypeId( result ) != GEOS_LINESTRING )
  {
    GEOSGeom_destroy( result );
    return 0;
  }
  return result;
}

int QgsGeometry::topologicalTestPointsSplit( const GEOSGeometry* splitLine, QList<QgsPoint>& testPoints ) const
{
  //Find out the intersection points between splitLineGeos and this geometry.
  //These points need to be tested for topological correctness by the calling function
  //if topological editing is enabled

  testPoints.clear();
  GEOSGeometry* intersectionGeom = GEOSIntersection( mGeos, splitLine );
  if ( !intersectionGeom )
  {
    return 1;
  }

  bool simple = false;
  int nIntersectGeoms = 1;
  if ( GEOSGeomTypeId( intersectionGeom ) == GEOS_LINESTRING || GEOSGeomTypeId( intersectionGeom ) == GEOS_POINT )
  {
    simple = true;
  }

  if ( !simple )
  {
    nIntersectGeoms = GEOSGetNumGeometries( intersectionGeom );
  }

  for ( int i = 0; i < nIntersectGeoms; ++i )
  {
    const GEOSGeometry* currentIntersectGeom;
    if ( simple )
    {
      currentIntersectGeom = intersectionGeom;
    }
    else
    {
      currentIntersectGeom = GEOSGetGeometryN( intersectionGeom, i );
    }

    const GEOSCoordSequence* lineSequence = GEOSGeom_getCoordSeq( currentIntersectGeom );
    unsigned int sequenceSize = 0;
    double x, y;
    if ( GEOSCoordSeq_getSize( lineSequence, &sequenceSize ) != 0 )
    {
      for ( unsigned int i = 0; i < sequenceSize; ++i )
      {
        if ( GEOSCoordSeq_getX( lineSequence, i, &x ) != 0 )
        {
          if ( GEOSCoordSeq_getY( lineSequence, i, &y ) != 0 )
          {
            testPoints.push_back( QgsPoint( x, y ) );
          }
        }
      }
    }
  }
  GEOSGeom_destroy( intersectionGeom );
  return 0;
}

GEOSGeometry *QgsGeometry::nodeGeometries( const GEOSGeometry *splitLine, const GEOSGeometry *geom )
{
  if ( !splitLine || !geom )
  {
    return 0;
  }

  GEOSGeometry *geometryBoundary = 0;
  if ( GEOSGeomTypeId( geom ) == GEOS_POLYGON || GEOSGeomTypeId( geom ) == GEOS_MULTIPOLYGON )
  {
    geometryBoundary = GEOSBoundary( geom );
  }
  else
  {
    geometryBoundary = GEOSGeom_clone( geom );
  }

  GEOSGeometry *splitLineClone = GEOSGeom_clone( splitLine );
  GEOSGeometry *unionGeometry = GEOSUnion( splitLineClone, geometryBoundary );
  GEOSGeom_destroy( splitLineClone );

  GEOSGeom_destroy( geometryBoundary );
  return unionGeometry;
}

int QgsGeometry::lineContainedInLine( const GEOSGeometry* line1, const GEOSGeometry* line2 )
{
  if ( !line1 || !line2 )
  {
    return -1;
  }


  double bufferDistance = 0.00001;
  if ( geomInDegrees( line2 ) ) //use more accurate tolerance for degrees
  {
    bufferDistance = 0.00000001;
  }
  GEOSGeometry* bufferGeom = GEOSBuffer( line2, bufferDistance, DEFAULT_QUADRANT_SEGMENTS );
  if ( !bufferGeom )
  {
    return -2;
  }

  GEOSGeometry* intersectionGeom = GEOSIntersection( bufferGeom, line1 );

  //compare ratio between line1Length and intersectGeomLength (usually close to 1 if line1 is contained in line2)
  double intersectGeomLength;
  double line1Length;

  GEOSLength( intersectionGeom, &intersectGeomLength );
  GEOSLength( line1, &line1Length );

  GEOSGeom_destroy( bufferGeom );
  GEOSGeom_destroy( intersectionGeom );

  double intersectRatio = line1Length / intersectGeomLength;
  if ( intersectRatio > 0.9 && intersectRatio < 1.1 )
  {
    return 1;
  }
  return 0;
}

int QgsGeometry::pointContainedInLine( const GEOSGeometry* point, const GEOSGeometry* line )
{
  if ( !point || !line )
  {
    return -1;
  }

  double bufferDistance = 0.000001;
  if ( geomInDegrees( line ) )
  {
    bufferDistance = 0.00000001;
  }
  GEOSGeometry* lineBuffer = GEOSBuffer( line, bufferDistance, 8 );
  if ( !lineBuffer )
  {
    return -2;
  }

  bool contained = false;
  if ( GEOSContains( lineBuffer, point ) == 1 )
  {
    contained = true;
  }

  GEOSGeom_destroy( lineBuffer );
  return contained;
}

bool QgsGeometry::geomInDegrees( const GEOSGeometry* geom )
{
  GEOSGeometry* bbox = GEOSEnvelope( geom );
  if ( !bbox )
  {
    return false;
  }

  const GEOSGeometry* bBoxRing = GEOSGetExteriorRing( bbox );
  if ( !bBoxRing )
  {
    return false;
  }
  const GEOSCoordSequence* bBoxCoordSeq = GEOSGeom_getCoordSeq( bBoxRing );

  if ( !bBoxCoordSeq )
  {
    return false;
  }

  unsigned int nCoords = 0;
  if ( !GEOSCoordSeq_getSize( bBoxCoordSeq, &nCoords ) )
  {
    return false;
  }

  double x, y;
  for ( unsigned int i = 0; i < ( nCoords - 1 ); ++i )
  {
    GEOSCoordSeq_getX( bBoxCoordSeq, i, &x );
    if ( x > 180 || x < -180 )
    {
      return false;
    }
    GEOSCoordSeq_getY( bBoxCoordSeq, i, &y );
    if ( y > 90 || y < -90 )
    {
      return false;
    }
  }

  return true;
}

int QgsGeometry::numberOfGeometries( GEOSGeometry* g ) const
{
  if ( !g )
  {
    return 0;
  }
  int geometryType = GEOSGeomTypeId( g );
  if ( geometryType == GEOS_POINT || geometryType == GEOS_LINESTRING || geometryType == GEOS_LINEARRING
       || geometryType == GEOS_POLYGON )
  {
    return 1;
  }

  //calling GEOSGetNumGeometries is save for multi types and collections also in geos2
  return GEOSGetNumGeometries( g );
}

int QgsGeometry::mergeGeometriesMultiTypeSplit( QVector<GEOSGeometry*>& splitResult )
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return 1;
  }

  //convert mGeos to geometry collection
  int type = GEOSGeomTypeId( mGeos );
  if ( type != GEOS_GEOMETRYCOLLECTION &&
       type != GEOS_MULTILINESTRING &&
       type != GEOS_MULTIPOLYGON &&
       type != GEOS_MULTIPOINT )
  {
    return 0;
  }

  QVector<GEOSGeometry*> copyList = splitResult;
  splitResult.clear();

  //collect all the geometries that belong to the initial multifeature
  QVector<GEOSGeometry*> unionGeom;

  for ( int i = 0; i < copyList.size(); ++i )
  {
    //is this geometry a part of the original multitype?
    bool isPart = false;
    for ( int j = 0; j < GEOSGetNumGeometries( mGeos ); j++ )
    {
      if ( GEOSEquals( copyList[i], GEOSGetGeometryN( mGeos, j ) ) )
      {
        isPart = true;
        break;
      }
    }

    if ( isPart )
    {
      unionGeom << copyList[i];
    }
    else
    {
      QVector<GEOSGeometry*> geomVector;
      geomVector << copyList[i];

      if ( type == GEOS_MULTILINESTRING )
      {
        splitResult << createGeosCollection( GEOS_MULTILINESTRING, geomVector );
      }
      else if ( type == GEOS_MULTIPOLYGON )
      {
        splitResult << createGeosCollection( GEOS_MULTIPOLYGON, geomVector );
      }
      else
      {
        GEOSGeom_destroy( copyList[i] );
      }
    }
  }

  //make multifeature out of unionGeom
  if ( unionGeom.size() > 0 )
  {
    if ( type == GEOS_MULTILINESTRING )
    {
      splitResult << createGeosCollection( GEOS_MULTILINESTRING, unionGeom );
    }
    else if ( type == GEOS_MULTIPOLYGON )
    {
      splitResult << createGeosCollection( GEOS_MULTIPOLYGON, unionGeom );
    }
  }
  else
  {
    unionGeom.clear();
  }

  return 0;
}

QgsPoint QgsGeometry::asPoint( unsigned char*& ptr, bool hasZValue )
{
  ptr += 5;
  double* x = ( double * )( ptr );
  double* y = ( double * )( ptr + sizeof( double ) );
  ptr += 2 * sizeof( double );

  if ( hasZValue )
    ptr += sizeof( double );

  return QgsPoint( *x, *y );
}


QgsPolyline QgsGeometry::asPolyline( unsigned char*& ptr, bool hasZValue )
{
  double x, y;
  ptr += 5;
  unsigned int nPoints = *(( int* )ptr );
  ptr += 4;

  QgsPolyline line( nPoints );

  // Extract the points from the WKB format into the x and y vectors.
  for ( uint i = 0; i < nPoints; ++i )
  {
    x = *(( double * ) ptr );
    y = *(( double * )( ptr + sizeof( double ) ) );

    ptr += 2 * sizeof( double );

    line[i] = QgsPoint( x, y );

    if ( hasZValue ) // ignore Z value
      ptr += sizeof( double );
  }

  return line;
}


QgsPolygon QgsGeometry::asPolygon( unsigned char*& ptr, bool hasZValue )
{
  double x, y;

  ptr += 5;

  // get number of rings in the polygon
  unsigned int numRings = *(( int* )ptr );
  ptr += 4;

  if ( numRings == 0 )  // sanity check for zero rings in polygon
    return QgsPolygon();

  QgsPolygon rings( numRings );

  for ( uint idx = 0; idx < numRings; idx++ )
  {
    uint nPoints = *(( int* )ptr );
    ptr += 4;

    QgsPolyline ring( nPoints );

    for ( uint jdx = 0; jdx < nPoints; jdx++ )
    {
      x = *(( double * ) ptr );
      y = *(( double * )( ptr + sizeof( double ) ) );

      ptr += 2 * sizeof( double );

      if ( hasZValue )
        ptr += sizeof( double );

      ring[jdx] = QgsPoint( x, y );
    }

    rings[idx] = ring;
  }

  return rings;
}


QgsPoint QgsGeometry::asPoint()
{
  QGis::WkbType type = wkbType();
  if ( type != QGis::WKBPoint && type != QGis::WKBPoint25D )
    return QgsPoint( 0, 0 );

  unsigned char* ptr = mGeometry;
  return asPoint( ptr, type == QGis::WKBPoint25D );
}

QgsPolyline QgsGeometry::asPolyline()
{
  QGis::WkbType type = wkbType();
  if ( type != QGis::WKBLineString && type != QGis::WKBLineString25D )
    return QgsPolyline();

  unsigned char *ptr = mGeometry;
  return asPolyline( ptr, type == QGis::WKBLineString25D );
}

QgsPolygon QgsGeometry::asPolygon()
{
  QGis::WkbType type = wkbType();
  if ( type != QGis::WKBPolygon && type != QGis::WKBPolygon25D )
    return QgsPolygon();

  unsigned char *ptr = mGeometry;
  return asPolygon( ptr, type == QGis::WKBPolygon25D );
}

QgsMultiPoint QgsGeometry::asMultiPoint()
{
  QGis::WkbType type = wkbType();
  if ( type != QGis::WKBMultiPoint && type != QGis::WKBMultiPoint25D )
    return QgsMultiPoint();

  bool hasZValue = ( type == QGis::WKBMultiPoint25D );

  unsigned char* ptr = mGeometry + 5;
  unsigned int nPoints = *(( int* )ptr );
  ptr += 4;

  QgsMultiPoint points( nPoints );
  for ( uint i = 0; i < nPoints; i++ )
  {
    points[i] = asPoint( ptr, hasZValue );
  }

  return points;
}

QgsMultiPolyline QgsGeometry::asMultiPolyline()
{
  QGis::WkbType type = wkbType();
  if ( type != QGis::WKBMultiLineString && type != QGis::WKBMultiLineString25D )
    return QgsMultiPolyline();

  bool hasZValue = ( type == QGis::WKBMultiLineString25D );

  unsigned char* ptr = mGeometry + 5;
  unsigned int numLineStrings = *(( int* )ptr );
  ptr += 4;

  QgsMultiPolyline lines( numLineStrings );

  for ( uint i = 0; i < numLineStrings; i++ )
  {
    lines[i] = asPolyline( ptr, hasZValue );
  }

  return lines;
}

QgsMultiPolygon QgsGeometry::asMultiPolygon()
{
  QGis::WkbType type = wkbType();
  if ( type != QGis::WKBMultiPolygon && type != QGis::WKBMultiPolygon25D )
    return QgsMultiPolygon();

  bool hasZValue = ( type == QGis::WKBMultiPolygon25D );

  unsigned char* ptr = mGeometry + 5;
  unsigned int numPolygons = *(( int* )ptr );
  ptr += 4;

  QgsMultiPolygon polygons( numPolygons );

  for ( uint i = 0; i < numPolygons; i++ )
  {
    polygons[i] = asPolygon( ptr, hasZValue );
  }

  return polygons;
}

double QgsGeometry::area()
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return -1.0;
  }

  double area;

  try
  {
    if ( GEOSArea( mGeos, &area ) == 0 )
      return -1.0;
  }
  CATCH_GEOS( -1.0 )

  return area;
}

double QgsGeometry::length()
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return -1.0;
  }

  double length;

  try
  {
    if ( GEOSLength( mGeos, &length ) == 0 )
      return -1.0;
  }
  CATCH_GEOS( -1.0 )

  return length;
}
double QgsGeometry::distance( QgsGeometry& geom )
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( geom.mDirtyGeos )
  {
    geom.exportWkbToGeos();
  }

  if ( !mGeos || !geom.mGeos )
    return -1.0;

  double dist = -1.0;

  try
  {
    GEOSDistance( mGeos, geom.mGeos, &dist );
  }
  CATCH_GEOS( -1.0 )

  return dist;
}


QgsGeometry* QgsGeometry::buffer( double distance, int segments )
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return 0;
  }

  try
  {
    return fromGeosGeom( GEOSBuffer( mGeos, distance, segments ) );
  }
  CATCH_GEOS( 0 )
}

QgsGeometry* QgsGeometry::simplify( double tolerance )
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return 0;
  }
  try
  {
    return fromGeosGeom( GEOSSimplify( mGeos, tolerance ) );
  }
  CATCH_GEOS( 0 )
}

QgsGeometry* QgsGeometry::centroid()
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return 0;
  }
  try
  {
    return fromGeosGeom( GEOSGetCentroid( mGeos ) );
  }
  CATCH_GEOS( 0 )
}

QgsGeometry* QgsGeometry::convexHull()
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return 0;
  }

  try
  {
    return fromGeosGeom( GEOSConvexHull( mGeos ) );
  }
  CATCH_GEOS( 0 )
}

QgsGeometry* QgsGeometry::interpolate( double distance )
{
#if defined(GEOS_VERSION_MAJOR) && defined(GEOS_VERSION_MINOR) && \
    ((GEOS_VERSION_MAJOR>3) || ((GEOS_VERSION_MAJOR==3) && (GEOS_VERSION_MINOR>=2)))
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( !mGeos )
  {
    return 0;
  }

  try
  {
    return fromGeosGeom( GEOSInterpolate( mGeos, distance ) );
  }
  CATCH_GEOS( 0 )
#else
  QgsMessageLog::logMessage( QObject::tr( "GEOS prior to 3.2 doesn't support GEOSInterpolate" ), QObject::tr( "GEOS" ) );
#endif
}

QgsGeometry* QgsGeometry::intersection( QgsGeometry* geometry )
{
  if ( !geometry )
  {
    return NULL;
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( geometry->mDirtyGeos )
  {
    geometry->exportWkbToGeos();
  }


  if ( !mGeos || !geometry->mGeos )
  {
    return 0;
  }

  try
  {
    return fromGeosGeom( GEOSIntersection( mGeos, geometry->mGeos ) );
  }
  CATCH_GEOS( 0 )
}

QgsGeometry* QgsGeometry::combine( QgsGeometry* geometry )
{
  if ( !geometry )
  {
    return NULL;
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( geometry->mDirtyGeos )
  {
    geometry->exportWkbToGeos();
  }

  if ( !mGeos || !geometry->mGeos )
  {
    return 0;
  }

  try
  {
    GEOSGeometry* unionGeom = GEOSUnion( mGeos, geometry->mGeos );
    if ( type() == QGis::Line )
    {
      GEOSGeometry* mergedGeom = GEOSLineMerge( unionGeom );
      if ( mergedGeom )
      {
        GEOSGeom_destroy( unionGeom );
        unionGeom = mergedGeom;
      }
    }
    return fromGeosGeom( unionGeom );
  }
  CATCH_GEOS( new QgsGeometry( *this ) ) //return this geometry if union not possible
}

QgsGeometry* QgsGeometry::difference( QgsGeometry* geometry )
{
  if ( !geometry )
  {
    return NULL;
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( geometry->mDirtyGeos )
  {
    geometry->exportWkbToGeos();
  }

  if ( !mGeos || !geometry->mGeos )
  {
    return 0;
  }

  try
  {
    return fromGeosGeom( GEOSDifference( mGeos, geometry->mGeos ) );
  }
  CATCH_GEOS( 0 )
}

QgsGeometry* QgsGeometry::symDifference( QgsGeometry* geometry )
{
  if ( !geometry )
  {
    return NULL;
  }

  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }
  if ( geometry->mDirtyGeos )
  {
    geometry->exportWkbToGeos();
  }

  if ( !mGeos || !geometry->mGeos )
  {
    return 0;
  }

  try
  {
    return fromGeosGeom( GEOSSymDifference( mGeos, geometry->mGeos ) );
  }
  CATCH_GEOS( 0 )
}

QList<QgsGeometry*> QgsGeometry::asGeometryCollection()
{
  if ( mDirtyGeos )
  {
    exportWkbToGeos();
  }

  if ( !mGeos )
  {
    return QList<QgsGeometry*>();
  }

  int type = GEOSGeomTypeId( mGeos );
  QgsDebugMsg( "geom type: " + QString::number( type ) );

  QList<QgsGeometry*> geomCollection;

  if ( type != GEOS_MULTIPOINT &&
       type != GEOS_MULTILINESTRING &&
       type != GEOS_MULTIPOLYGON &&
       type != GEOS_GEOMETRYCOLLECTION )
  {
    // we have a single-part geometry - put there a copy of this one
    geomCollection.append( new QgsGeometry( *this ) );
    return geomCollection;
  }

  int count = GEOSGetNumGeometries( mGeos );
  QgsDebugMsg( "geom count: " + QString::number( count ) );

  for ( int i = 0; i < count; ++i )
  {
    const GEOSGeometry * geometry = GEOSGetGeometryN( mGeos, i );
    geomCollection.append( fromGeosGeom( GEOSGeom_clone( geometry ) ) );
  }

  return geomCollection;
}


bool QgsGeometry::deleteRing( int ringNum, int partNum )
{
  if ( ringNum <= 0 || partNum < 0 )
    return false;

  switch ( wkbType() )
  {
    case QGis::WKBPolygon25D:
    case QGis::WKBPolygon:
    {
      if ( partNum != 0 )
        return false;

      QgsPolygon polygon = asPolygon();
      if ( ringNum >= polygon.count() )
        return false;

      polygon.remove( ringNum );

      QgsGeometry* g2 = QgsGeometry::fromPolygon( polygon );
      *this = *g2;
      delete g2;
      return true;
    }

    case QGis::WKBMultiPolygon25D:
    case QGis::WKBMultiPolygon:
    {
      QgsMultiPolygon mpolygon = asMultiPolygon();

      if ( partNum >= mpolygon.count() )
        return false;

      if ( ringNum >= mpolygon[partNum].count() )
        return false;

      mpolygon[partNum].remove( ringNum );

      QgsGeometry* g2 = QgsGeometry::fromMultiPolygon( mpolygon );
      *this = *g2;
      delete g2;
      return true;
    }

    default:
      return false; // only makes sense with polygons and multipolygons
  }
}


bool QgsGeometry::deletePart( int partNum )
{
  if ( partNum < 0 )
    return false;

  switch ( wkbType() )
  {
    case QGis::WKBMultiPoint25D:
    case QGis::WKBMultiPoint:
    {
      QgsMultiPoint mpoint = asMultiPoint();

      if ( partNum >= mpoint.size() || mpoint.size() == 1 )
        return false;

      mpoint.remove( partNum );

      QgsGeometry* g2 = QgsGeometry::fromMultiPoint( mpoint );
      *this = *g2;
      delete g2;
      break;
    }

    case QGis::WKBMultiLineString25D:
    case QGis::WKBMultiLineString:
    {
      QgsMultiPolyline mline = asMultiPolyline();

      if ( partNum >= mline.size() || mline.size() == 1 )
        return false;

      mline.remove( partNum );

      QgsGeometry* g2 = QgsGeometry::fromMultiPolyline( mline );
      *this = *g2;
      delete g2;
      break;
    }

    case QGis::WKBMultiPolygon25D:
    case QGis::WKBMultiPolygon:
    {
      QgsMultiPolygon mpolygon = asMultiPolygon();

      if ( partNum >= mpolygon.size() || mpolygon.size() == 1 )
        return false;

      mpolygon.remove( partNum );

      QgsGeometry* g2 = QgsGeometry::fromMultiPolygon( mpolygon );
      *this = *g2;
      delete g2;
      break;
    }

    default:
      // single part geometries are ignored
      return false;
  }

  return true;
}

int QgsGeometry::avoidIntersections( QMap<QgsVectorLayer*, QSet< QgsFeatureId > > ignoreFeatures )
{
  int returnValue = 0;

  //check if g has polygon type
  if ( type() != QGis::Polygon )
  {
    return 1;
  }

  QGis::WkbType geomTypeBeforeModification = wkbType();

  //read avoid intersections list from project properties
  bool listReadOk;
  QStringList avoidIntersectionsList = QgsProject::instance()->readListEntry( "Digitizing", "/AvoidIntersectionsList", QStringList(), &listReadOk );
  if ( !listReadOk )
  {
    return true; //no intersections stored in project does not mean error
  }

  //go through list, convert each layer to vector layer and call QgsVectorLayer::removePolygonIntersections for each
  QgsVectorLayer* currentLayer = 0;
  QStringList::const_iterator aIt = avoidIntersectionsList.constBegin();
  for ( ; aIt != avoidIntersectionsList.constEnd(); ++aIt )
  {
    currentLayer = dynamic_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( *aIt ) );
    if ( currentLayer )
    {
      QgsFeatureIds ignoreIds;
      QMap<QgsVectorLayer*, QSet<qint64> >::const_iterator ignoreIt = ignoreFeatures.find( currentLayer );
      if ( ignoreIt != ignoreFeatures.constEnd() )
      {
        ignoreIds = ignoreIt.value();
      }

      if ( currentLayer->removePolygonIntersections( this, ignoreIds ) != 0 )
      {
        returnValue = 3;
      }
    }
  }

  //make sure the geometry still has the same type (e.g. no change from polygon to multipolygon)
  if ( wkbType() != geomTypeBeforeModification )
  {
    return 2;
  }

  return returnValue;
}

void QgsGeometry::validateGeometry( QList<Error> &errors )
{
  QgsGeometryValidator::validateGeometry( this, errors );
}

bool QgsGeometry::isGeosValid()
{
  try
  {
    GEOSGeometry *g = asGeos();

    if ( !g )
      return false;

    return GEOSisValid( g );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    return false;
  }
}

bool QgsGeometry::isGeosEqual( QgsGeometry &g )
{
  return geosRelOp( GEOSEquals, this, &g );
}

bool QgsGeometry::isGeosEmpty()
{
  try
  {
    GEOSGeometry *g = asGeos();

    if ( !g )
      return false;

    return GEOSisEmpty( g );
  }
  catch ( GEOSException &e )
  {
    QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
    return false;
  }
}

double QgsGeometry::leftOf( double x, double y, double& x1, double& y1, double& x2, double& y2 )
{
  double f1 = x - x1;
  double f2 = y2 - y1;
  double f3 = y - y1;
  double f4 = x2 - x1;
  return f1*f2 - f3*f4;
}