Quantum GIS API Documentation  1.8
Classes | Public Member Functions | Static Public Member Functions | Private Member Functions | Static Private Member Functions | Private Attributes | Static Private Attributes
QgsGeometry Class Reference

A geometry is the spatial representation of a feature. More...

#include <qgsgeometry.h>

List of all members.

Classes

class  Error

Public Member Functions

 QgsGeometry ()
 Constructor.
 QgsGeometry (QgsGeometry const &)
 copy constructor will prompt a deep copy of the object
QgsGeometryoperator= (QgsGeometry const &rhs)
 assignments will prompt a deep copy of the object
 ~QgsGeometry ()
 Destructor.
void fromGeos (GEOSGeometry *geos)
 Set the geometry, feeding in a geometry in GEOS format.
void fromWkb (unsigned char *wkb, size_t length)
 Set the geometry, feeding in the buffer containing OGC Well-Known Binary and the buffer's length.
unsigned char * asWkb ()
 Returns the buffer containing this geometry in WKB format.
size_t wkbSize ()
 Returns the size of the WKB in asWkb().
GEOSGeometry * asGeos ()
 Returns a geos geomtry.
QGis::WkbType wkbType ()
 Returns type of wkb (point / linestring / polygon etc.)
QGis::GeometryType type ()
 Returns type of the vector.
bool isMultipart ()
 Returns true if wkb of the geometry is of WKBMulti* type.
bool isGeosEqual (QgsGeometry &)
 compare geometries using GEOS
bool isGeosValid ()
 check validity using GEOS
bool isGeosEmpty ()
 check if geometry is empty using GEOS
double area ()
 get area of geometry using GEOS
double length ()
 get length of geometry using GEOS
double distance (QgsGeometry &geom)
QgsPoint closestVertex (const QgsPoint &point, int &atVertex, int &beforeVertex, int &afterVertex, double &sqrDist)
 Returns the vertex closest to the given point, the corresponding vertex index, squared distance snap point / target point and the indices of the vertices before/after.
void adjacentVertices (int atVertex, int &beforeVertex, int &afterVertex)
 Returns the indexes of the vertices before and after the given vertex index.
bool insertVertex (double x, double y, int beforeVertex)
 Insert a new vertex before the given vertex index, ring and item (first number is index 0) If the requested vertex number (beforeVertex.back()) is greater than the last actual vertex on the requested ring and item, it is assumed that the vertex is to be appended instead of inserted.
bool moveVertex (double x, double y, int atVertex)
 Moves the vertex at the given position number and item (first number is index 0) to the given coordinates.
bool deleteVertex (int atVertex)
 Deletes the vertex at the given position number and item (first number is index 0) Returns false if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point), or if the number of remaining verticies in the linestring would be less than two.
QgsPoint vertexAt (int atVertex)
 Returns coordinates of a vertex.
double sqrDistToVertexAt (QgsPoint &point, int atVertex)
 Returns the squared cartesian distance between the given point to the given vertex index (vertex at the given position number, ring and item (first number is index 0))
double closestVertexWithContext (const QgsPoint &point, int &atVertex)
 Searches for the the closest vertex in this geometry to the given point.
double closestSegmentWithContext (const QgsPoint &point, QgsPoint &minDistPoint, int &afterVertex, double *leftOf=0, double epsilon=DEFAULT_SEGMENT_EPSILON)
 Searches for the closest segment of geometry to the given point.
int addRing (const QList< QgsPoint > &ring)
 Adds a new ring to this geometry.
int addPart (const QList< QgsPoint > &points)
 Adds a new island polygon to a multipolygon feature.
Q_DECL_DEPRECATED int addIsland (const QList< QgsPoint > &points)
int translate (double dx, double dy)
 Translate this geometry by dx, dy.
int transform (const QgsCoordinateTransform &ct)
 Transform this geometry as described by CoordinateTranasform ct.
int splitGeometry (const QList< QgsPoint > &splitLine, QList< QgsGeometry * > &newGeometries, bool topological, QList< QgsPoint > &topologyTestPoints)
 Splits this geometry according to a given line.
int reshapeGeometry (const QList< QgsPoint > &reshapeWithLine)
 Replaces a part of this geometry with another line.
int makeDifference (QgsGeometry *other)
 Changes this geometry such that it does not intersect the other geometry.
QgsRectangle boundingBox ()
 Returns the bounding box of this feature.
bool intersects (const QgsRectangle &r)
 Test for intersection with a rectangle (uses GEOS)
bool intersects (QgsGeometry *geometry)
 Test for intersection with a geometry (uses GEOS)
bool contains (QgsPoint *p)
 Test for containment of a point (uses GEOS)
bool contains (QgsGeometry *geometry)
 Test for if geometry is contained in an other (uses GEOS)
bool disjoint (QgsGeometry *geometry)
 Test for if geometry is disjoint of an other (uses GEOS)
bool equals (QgsGeometry *geometry)
 Test for if geometry equals an other (uses GEOS)
bool touches (QgsGeometry *geometry)
 Test for if geometry touch an other (uses GEOS)
bool overlaps (QgsGeometry *geometry)
 Test for if geometry overlaps an other (uses GEOS)
bool within (QgsGeometry *geometry)
 Test for if geometry is within an other (uses GEOS)
bool crosses (QgsGeometry *geometry)
 Test for if geometry crosses an other (uses GEOS)
QgsGeometrybuffer (double distance, int segments)
 Returns a buffer region around this geometry having the given width and with a specified number of segments used to approximate curves.
QgsGeometrysimplify (double tolerance)
 Returns a simplified version of this geometry using a specified tolerance value.
QgsGeometrycentroid ()
 Returns the center of mass of a geometry.
QgsGeometryconvexHull ()
 Returns the smallest convex polygon that contains all the points in the geometry.
QgsGeometryintersection (QgsGeometry *geometry)
 Returns a geometry representing the points shared by this geometry and other.
QgsGeometrycombine (QgsGeometry *geometry)
 Returns a geometry representing all the points in this geometry and other (a union geometry operation).
QgsGeometrydifference (QgsGeometry *geometry)
 Returns a geometry representing the points making up this geometry that do not make up other.
QgsGeometrysymDifference (QgsGeometry *geometry)
 Returns a Geometry representing the points making up this Geometry that do not make up other.
QString exportToWkt ()
 Exports the geometry to mWkt.
QString exportToGeoJSON ()
 Exports the geometry to mGeoJSON.
QgsPoint asPoint ()
 return contents of the geometry as a point if wkbType is WKBPoint, otherwise returns [0,0]
QgsPolyline asPolyline ()
 return contents of the geometry as a polyline if wkbType is WKBLineString, otherwise an empty list
QgsPolygon asPolygon ()
 return contents of the geometry as a polygon if wkbType is WKBPolygon, otherwise an empty list
QgsMultiPoint asMultiPoint ()
 return contents of the geometry as a multi point if wkbType is WKBMultiPoint, otherwise an empty list
QgsMultiPolyline asMultiPolyline ()
 return contents of the geometry as a multi linestring if wkbType is WKBMultiLineString, otherwise an empty list
QgsMultiPolygon asMultiPolygon ()
 return contents of the geometry as a multi polygon if wkbType is WKBMultiPolygon, otherwise an empty list
QList< QgsGeometry * > asGeometryCollection ()
 return contents of the geometry as a list of geometries
bool deleteRing (int ringNum, int partNum=0)
 delete a ring in polygon or multipolygon.
bool deletePart (int partNum)
 delete part identified by the part number
bool convertToMultiType ()
 Converts single type geometry into multitype geometry e.g.
int avoidIntersections ()
 Modifies geometry to avoid intersections with the layers specified in project properties.
void validateGeometry (QList< Error > &errors)
 Validate geometry and produce a list of geometry errors.

Static Public Member Functions

static QgsGeometryfromWkt (QString wkt)
 static method that creates geometry from Wkt
static QgsGeometryfromPoint (const QgsPoint &point)
 construct geometry from a point
static QgsGeometryfromMultiPoint (const QgsMultiPoint &multipoint)
 construct geometry from a multipoint
static QgsGeometryfromPolyline (const QgsPolyline &polyline)
 construct geometry from a polyline
static QgsGeometryfromMultiPolyline (const QgsMultiPolyline &multiline)
 construct geometry from a multipolyline
static QgsGeometryfromPolygon (const QgsPolygon &polygon)
 construct geometry from a polygon
static QgsGeometryfromMultiPolygon (const QgsMultiPolygon &multipoly)
 construct geometry from a multipolygon
static QgsGeometryfromRect (const QgsRectangle &rect)
 construct geometry from a rectangle

Private Member Functions

bool exportWkbToGeos ()
 Converts from the WKB geometry to the GEOS geometry.
bool exportGeosToWkb ()
 Converts from the GEOS geometry to the WKB geometry.
bool insertVertex (double x, double y, int beforeVertex, const GEOSCoordSequence *old_sequence, GEOSCoordSequence **new_sequence)
 Insert a new vertex before the given vertex index (first number is index 0) in the given GEOS Coordinate Sequence.
void translateVertex (int &wkbPosition, double dx, double dy, bool hasZValue)
 Translates a single vertex by dx and dy.
void transformVertex (int &wkbPosition, const QgsCoordinateTransform &ct, bool hasZValue)
 Transforms a single vertex by ct.
int splitLinearGeometry (GEOSGeometry *splitLine, QList< QgsGeometry * > &newGeometries)
 Splits line/multiline geometries.
int splitPolygonGeometry (GEOSGeometry *splitLine, QList< QgsGeometry * > &newGeometries)
 Splits polygon/multipolygon geometries.
int topologicalTestPointsSplit (const GEOSGeometry *splitLine, QList< QgsPoint > &testPoints) const
 Finds out the points that need to be tested for topological correctnes if this geometry will be split.
int numberOfGeometries (GEOSGeometry *g) const
 Returns number of single geometry in a geos geometry.
int mergeGeometriesMultiTypeSplit (QVector< GEOSGeometry * > &splitResult)
QgsPoint asPoint (unsigned char *&ptr, bool hasZValue)
 return point from wkb
QgsPolyline asPolyline (unsigned char *&ptr, bool hasZValue)
 return polyline from wkb
QgsPolygon asPolygon (unsigned char *&ptr, bool hasZValue)
 return polygon from wkb
double leftOf (double x, double y, double &x1, double &y1, double &x2, double &y2)
 Returns < 0 if point(x/y) is left of the line x1,y1 -> x1,y2.

Static Private Member Functions

static GEOSGeometry * reshapeLine (const GEOSGeometry *origLine, const GEOSGeometry *reshapeLineGeos)
 Creates a new line from an original line and a reshape line.
static GEOSGeometry * reshapePolygon (const GEOSGeometry *polygon, const GEOSGeometry *reshapeLineGeos)
 Creates a new polygon replacing the part from the first to the second intersection with the reshape line.
static GEOSGeometry * nodeGeometries (const GEOSGeometry *splitLine, const GEOSGeometry *poly)
 Nodes together a split line and a (multi-) polygon geometry in a multilinestring.
static int lineContainedInLine (const GEOSGeometry *line1, const GEOSGeometry *line2)
 Tests if line1 is completely contained in line2.
static int pointContainedInLine (const GEOSGeometry *point, const GEOSGeometry *line)
 Tests if a point is on a line.
static bool geomInDegrees (const GEOSGeometry *geom)
 Tests if geom bounding rect is within -180 <= x <= 180, -90 <= y <= 90.
static bool geosRelOp (char(*op)(const GEOSGeometry *, const GEOSGeometry *), QgsGeometry *a, QgsGeometry *b)

Private Attributes

unsigned char * mGeometry
 pointer to geometry in binary WKB format This is the class' native implementation
size_t mGeometrySize
 size of geometry
GEOSGeometry * mGeos
 cached GEOS version of this geometry
bool mDirtyWkb
 If the geometry has been set since the last conversion to WKB.
bool mDirtyGeos
 If the geometry has been set since the last conversion to GEOS.

Static Private Attributes

static int refcount

Detailed Description

A geometry is the spatial representation of a feature.

Represents a geometry with input and output in formats specified by (at least) the Open Geospatial Consortium (WKB / Wkt), and containing various functions for geoprocessing of the geometry.

The geometry is represented internally by the OGC WKB format or as GEOS geometry. Some functions use WKB for their work, others use GEOS.

TODO: migrate completely to GEOS and only support WKB/Wkt import/export.

Author:
Brendan Morley

Definition at line 66 of file qgsgeometry.h.


Constructor & Destructor Documentation

Constructor.

Definition at line 185 of file qgsgeometry.cpp.

Referenced by asGeometryCollection(), and combine().

copy constructor will prompt a deep copy of the object

Definition at line 194 of file qgsgeometry.cpp.

References mGeometry, mGeometrySize, and mGeos.

Destructor.

Definition at line 218 of file qgsgeometry.cpp.

References mGeometry, and mGeos.


Member Function Documentation

Q_DECL_DEPRECATED int QgsGeometry::addIsland ( const QList< QgsPoint > &  points) [inline]

Definition at line 259 of file qgsgeometry.h.

int QgsGeometry::addPart ( const QList< QgsPoint > &  points)

Adds a new island polygon to a multipolygon feature.

Returns:
0 in case of success, 1 if not a multipolygon, 2 if ring is not a valid geometry, 3 if new polygon ring not disjoint with existing polygons of the feature

Definition at line 2845 of file qgsgeometry.cpp.

References convertToMultiType(), createGeosCollection(), createGeosLinearRing(), createGeosLineString(), createGeosPoint(), createGeosPolygon(), exportWkbToGeos(), isMultipart(), QGis::Line, QgsMessageLog::logMessage(), mDirtyGeos, mDirtyWkb, mGeos, QGis::Point, QGis::Polygon, QgsDebugMsg, type(), and GEOSException::what().

Referenced by QgsVectorLayer::addPart().

int QgsGeometry::addRing ( const QList< QgsPoint > &  ring)

Adds a new ring to this geometry.

This makes only sense for polygon and multipolygons.

Returns:
0 in case of success (ring added), 1 problem with geometry type, 2 ring not closed, 3 ring is not valid geometry, 4 ring not disjoint with existing rings, 5 no polygon found which contained the ring

Definition at line 2653 of file qgsgeometry.cpp.

References createGeosCollection(), createGeosLinearRing(), createGeosPolygon(), exportWkbToGeos(), QgsMessageLog::logMessage(), mDirtyGeos, mDirtyWkb, mGeos, QGis::Polygon, throwGEOSException(), type(), GEOSException::what(), QGis::WKBMultiPolygon, QGis::WKBPolygon, and wkbType().

Referenced by QgsVectorLayer::addRing().

void QgsGeometry::adjacentVertices ( int  atVertex,
int &  beforeVertex,
int &  afterVertex 
)

Returns the indexes of the vertices before and after the given vertex index.

This function takes into account the following factors:

1. If the given vertex index is at the end of a linestring, the adjacent index will be -1 (for "no adjacent vertex") 2. If the given vertex index is at the end of a linear ring (such as in a polygon), the adjacent index will take into account the first vertex is equal to the last vertex (and will skip equal vertex positions).

Definition at line 976 of file qgsgeometry.cpp.

References exportGeosToWkb(), mDirtyWkb, mGeometry, QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPoint, QGis::WKBPolygon, QGis::WKBPolygon25D, and wkbType().

double QgsGeometry::area ( )

get area of geometry using GEOS

Note:
added in 1.5

Definition at line 6278 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), and mGeos.

Referenced by QgsPalLayerSettings::checkMinimumSizeMM(), and QgsZonalStatistics::statisticsFromPreciseIntersection().

return contents of the geometry as a list of geometries

Note:
added in version 1.1

Definition at line 6526 of file qgsgeometry.cpp.

References exportWkbToGeos(), fromGeosGeom(), mGeos, QgsDebugMsg, and QgsGeometry().

Referenced by QgsGeometryAnalyzer::addEventLayerFeature(), and QgsGeometryAnalyzer::createOffsetGeometry().

GEOSGeometry * QgsGeometry::asGeos ( )

return contents of the geometry as a multi point if wkbType is WKBMultiPoint, otherwise an empty list

Definition at line 6213 of file qgsgeometry.cpp.

References asPoint(), mGeometry, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, and wkbType().

Referenced by QgsRubberBand::addGeometry(), and deletePart().

return contents of the geometry as a multi polygon if wkbType is WKBMultiPolygon, otherwise an empty list

Definition at line 6256 of file qgsgeometry.cpp.

References asPolygon(), mGeometry, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, and wkbType().

Referenced by QgsRubberBand::addGeometry(), QgsVectorLayer::addTopologicalPoints(), deletePart(), deleteRing(), QgsGeometryAnalyzer::perimeterMeasure(), and QgsGeometryValidator::run().

return contents of the geometry as a multi linestring if wkbType is WKBMultiLineString, otherwise an empty list

Definition at line 6234 of file qgsgeometry.cpp.

References asPolyline(), mGeometry, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, and wkbType().

Referenced by QgsRubberBand::addGeometry(), QgsVectorLayer::addTopologicalPoints(), deletePart(), QgsLineVectorLayerDirector::makeGraph(), and QgsGeometryValidator::run().

return contents of the geometry as a point if wkbType is WKBPoint, otherwise returns [0,0]

Definition at line 6183 of file qgsgeometry.cpp.

References mGeometry, QGis::WKBPoint, QGis::WKBPoint25D, and wkbType().

Referenced by QgsRubberBand::addGeometry(), asMultiPoint(), QgsPointDisplacementRenderer::createDisplacementGroups(), QgsGeometryAnalyzer::simpleMeasure(), and QgsSearchTreeNode::valueAgainst().

QgsPoint QgsGeometry::asPoint ( unsigned char *&  ptr,
bool  hasZValue 
) [private]

return point from wkb

Definition at line 6100 of file qgsgeometry.cpp.

return contents of the geometry as a polygon if wkbType is WKBPolygon, otherwise an empty list

Definition at line 6203 of file qgsgeometry.cpp.

References mGeometry, QGis::WKBPolygon, QGis::WKBPolygon25D, and wkbType().

Referenced by QgsRubberBand::addGeometry(), QgsVectorLayer::addTopologicalPoints(), asMultiPolygon(), deleteRing(), QgsGeometryAnalyzer::perimeterMeasure(), and QgsGeometryValidator::run().

QgsPolygon QgsGeometry::asPolygon ( unsigned char *&  ptr,
bool  hasZValue 
) [private]

return polygon from wkb

Definition at line 6141 of file qgsgeometry.cpp.

return contents of the geometry as a polyline if wkbType is WKBLineString, otherwise an empty list

Definition at line 6193 of file qgsgeometry.cpp.

References mGeometry, QGis::WKBLineString, QGis::WKBLineString25D, and wkbType().

Referenced by QgsRubberBand::addGeometry(), QgsVectorLayer::addTopologicalPoints(), asMultiPolyline(), QgsLineVectorLayerDirector::makeGraph(), QgsGeometryValidator::run(), and QgsSearchTreeNode::valueAgainst().

QgsPolyline QgsGeometry::asPolyline ( unsigned char *&  ptr,
bool  hasZValue 
) [private]

return polyline from wkb

Definition at line 6114 of file qgsgeometry.cpp.

unsigned char * QgsGeometry::asWkb ( )

Modifies geometry to avoid intersections with the layers specified in project properties.

Returns:
0 in case of success, 1 if geometry is not of polygon type, 2 if avoid intersection would change the geometry type, 3 other error during intersection removal
Note:
added in 1.5

Definition at line 6676 of file qgsgeometry.cpp.

References QgsMapLayerRegistry::instance(), QgsProject::instance(), QgsMapLayerRegistry::mapLayer(), QGis::Polygon, QgsProject::readListEntry(), QgsVectorLayer::removePolygonIntersections(), type(), and wkbType().

QgsGeometry * QgsGeometry::buffer ( double  distance,
int  segments 
)

Returns a buffer region around this geometry having the given width and with a specified number of segments used to approximate curves.

Definition at line 6342 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

Referenced by QgsGeometryAnalyzer::bufferFeature().

Returns the center of mass of a geometry.

Note:
for line based geometries, the center point of the line is returned, and for point based geometries, the point itself is returned

Definition at line 6377 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

Referenced by QgsGeometryAnalyzer::centroidFeature().

double QgsGeometry::closestSegmentWithContext ( const QgsPoint point,
QgsPoint minDistPoint,
int &  afterVertex,
double *  leftOf = 0,
double  epsilon = DEFAULT_SEGMENT_EPSILON 
)

Searches for the closest segment of geometry to the given point.

Parameters:
pointSpecifies the point for search
minDistPointReceives the nearest point on the segment
afterVertexReceives index of the vertex after the closest segment. The vertex before the closest segment is always afterVertex - 1
leftOfOut: Returns if the point lies on the left of right side of the segment ( < 0 means left, > 0 means right )
epsilonepsilon for segment snapping (added in 1.8)
Returns:
The squared cartesian distance is also returned in sqrDist, negative number on error

Definition at line 2408 of file qgsgeometry.cpp.

References exportGeosToWkb(), leftOf(), MathUtils::max(), mDirtyWkb, mGeometry, QgsDebugMsg, QgsPoint::sqrDistToSegment(), QgsPoint::toString(), QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, wkbType(), QGis::WKBUnknown, QgsPoint::x(), and QgsPoint::y().

Referenced by QgsGeometryAnalyzer::createPointOffset(), and QgsVectorLayer::snapToGeometry().

QgsPoint QgsGeometry::closestVertex ( const QgsPoint point,
int &  atVertex,
int &  beforeVertex,
int &  afterVertex,
double &  sqrDist 
)

Returns the vertex closest to the given point, the corresponding vertex index, squared distance snap point / target point and the indices of the vertices before/after.

The vertices before/after are -1 if not present

Definition at line 698 of file qgsgeometry.cpp.

References exportGeosToWkb(), MathUtils::max(), mDirtyWkb, mGeometry, QgsDebugMsg, QgsPoint::sqrDist(), QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, and wkbType().

Referenced by QgsVectorLayer::snapToGeometry().

double QgsGeometry::closestVertexWithContext ( const QgsPoint point,
int &  atVertex 
)

Searches for the the closest vertex in this geometry to the given point.

Parameters:
pointSpecifiest the point for search
atVertexReceives index of the closest vertex
Returns:
The squared cartesian distance is also returned in sqrDist, negative number on error

Definition at line 2360 of file qgsgeometry.cpp.

References exportWkbToGeos(), QgsMessageLog::logMessage(), MathUtils::max(), mGeos, QgsPoint::sqrDist(), and GEOSException::what().

Returns a geometry representing all the points in this geometry and other (a union geometry operation).

Note:
this operation is not called union since its a reserved word in C++.

Definition at line 6438 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), QGis::Line, mGeos, QgsGeometry(), and type().

Referenced by QgsGeometryAnalyzer::bufferFeature(), QgsGeometryAnalyzer::convexFeature(), and QgsGeometryAnalyzer::dissolveFeature().

bool QgsGeometry::contains ( QgsGeometry geometry)

Test for if geometry is contained in an other (uses GEOS)

Note:
added in 1.5

Definition at line 3881 of file qgsgeometry.cpp.

References geosRelOp().

Converts single type geometry into multitype geometry e.g.

a polygon into a multipolygon geometry with one polygon

Returns:
true in case of success and false else

Definition at line 5131 of file qgsgeometry.cpp.

References QgsApplication::endian(), mDirtyGeos, mGeometry, mGeometrySize, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, wkbType(), and QGis::WKBUnknown.

Referenced by addPart(), and makeDifference().

Returns the smallest convex polygon that contains all the points in the geometry.

Definition at line 6394 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

Referenced by QgsGeometryAnalyzer::convexFeature(), and QgsGeometryAnalyzer::convexHull().

bool QgsGeometry::crosses ( QgsGeometry geometry)

Test for if geometry crosses an other (uses GEOS)

Note:
added in 1.5

Definition at line 3911 of file qgsgeometry.cpp.

References geosRelOp().

bool QgsGeometry::deletePart ( int  partNum)
bool QgsGeometry::deleteRing ( int  ringNum,
int  partNum = 0 
)

delete a ring in polygon or multipolygon.

Ring 0 is outer ring and can't be deleted.

Returns:
true on success
Note:
added in version 1.2

Definition at line 6563 of file qgsgeometry.cpp.

References asMultiPolygon(), asPolygon(), fromMultiPolygon(), fromPolygon(), QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPolygon, QGis::WKBPolygon25D, and wkbType().

bool QgsGeometry::deleteVertex ( int  atVertex)

Deletes the vertex at the given position number and item (first number is index 0) Returns false if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point), or if the number of remaining verticies in the linestring would be less than two.

It is up to the caller to distinguish between these error conditions. (Or maybe we add another method to this object to help make the distinction?)

Definition at line 1506 of file qgsgeometry.cpp.

References exportGeosToWkb(), mDirtyGeos, mDirtyWkb, mGeometry, mGeometrySize, QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBNoGeometry, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, wkbType(), and QGis::WKBUnknown.

Referenced by QgsVectorLayer::deleteVertex().

Returns a geometry representing the points making up this geometry that do not make up other.

Definition at line 6474 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

bool QgsGeometry::disjoint ( QgsGeometry geometry)

Test for if geometry is disjoint of an other (uses GEOS)

Note:
added in 1.5

Definition at line 3886 of file qgsgeometry.cpp.

References geosRelOp().

double QgsGeometry::distance ( QgsGeometry geom)

Definition at line 6315 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), and mGeos.

bool QgsGeometry::equals ( QgsGeometry geometry)

Test for if geometry equals an other (uses GEOS)

Note:
added in 1.5

Definition at line 3891 of file qgsgeometry.cpp.

References geosRelOp().

bool QgsGeometry::exportGeosToWkb ( ) [private]
bool QgsGeometry::exportWkbToGeos ( ) [private]
void QgsGeometry::fromGeos ( GEOSGeometry *  geos)

Set the geometry, feeding in a geometry in GEOS format.

This class will take ownership of the buffer.

Definition at line 677 of file qgsgeometry.cpp.

References mDirtyGeos, mDirtyWkb, mGeometry, and mGeos.

Referenced by QgsGeometryAnalyzer::createOffsetGeometry(), and fromGeosGeom().

QgsGeometry * QgsGeometry::fromMultiPoint ( const QgsMultiPoint multipoint) [static]

construct geometry from a multipoint

Definition at line 444 of file qgsgeometry.cpp.

References createGeosCollection(), createGeosPoint(), fromGeosGeom(), QgsMessageLog::logMessage(), and GEOSException::what().

Referenced by deletePart(), and QgsGeometryAnalyzer::locateAlongMeasure().

QgsGeometry * QgsGeometry::fromMultiPolygon ( const QgsMultiPolygon multipoly) [static]

construct geometry from a multipolygon

Definition at line 490 of file qgsgeometry.cpp.

References createGeosCollection(), createGeosPolygon(), fromGeosGeom(), QgsMessageLog::logMessage(), and GEOSException::what().

Referenced by deletePart(), and deleteRing().

QgsGeometry * QgsGeometry::fromMultiPolyline ( const QgsMultiPolyline multiline) [static]
QgsGeometry * QgsGeometry::fromPoint ( const QgsPoint point) [static]

construct geometry from a point

Definition at line 429 of file qgsgeometry.cpp.

References createGeosPoint(), and fromGeosGeom().

QgsGeometry * QgsGeometry::fromPolygon ( const QgsPolygon polygon) [static]

construct geometry from a polygon

Definition at line 439 of file qgsgeometry.cpp.

References createGeosPolygon(), and fromGeosGeom().

Referenced by QgsRubberBand::asGeometry(), deleteRing(), and fromRect().

QgsGeometry * QgsGeometry::fromPolyline ( const QgsPolyline polyline) [static]

construct geometry from a polyline

Definition at line 434 of file qgsgeometry.cpp.

References createGeosLineString(), and fromGeosGeom().

Referenced by QgsRubberBand::asGeometry(), and QgsGeometryAnalyzer::perimeterMeasure().

QgsGeometry * QgsGeometry::fromRect ( const QgsRectangle rect) [static]
void QgsGeometry::fromWkb ( unsigned char *  wkb,
size_t  length 
)

Set the geometry, feeding in the buffer containing OGC Well-Known Binary and the buffer's length.

This class will take ownership of the buffer.

Definition at line 563 of file qgsgeometry.cpp.

References length(), mDirtyGeos, mDirtyWkb, mGeometry, mGeometrySize, and mGeos.

Referenced by QgsFeature::setGeometryAndOwnership().

QgsGeometry * QgsGeometry::fromWkt ( QString  wkt) [static]

static method that creates geometry from Wkt

Definition at line 409 of file qgsgeometry.cpp.

References fromGeosGeom(), QgsMessageLog::logMessage(), and GEOSException::what().

bool QgsGeometry::geomInDegrees ( const GEOSGeometry *  geom) [static, private]

Tests if geom bounding rect is within -180 <= x <= 180, -90 <= y <= 90.

Other methods may use more accurate tolerances if this is true

Definition at line 5958 of file qgsgeometry.cpp.

Referenced by lineContainedInLine(), and pointContainedInLine().

bool QgsGeometry::geosRelOp ( char(*)(const GEOSGeometry *, const GEOSGeometry *)  op,
QgsGeometry a,
QgsGeometry b 
) [static, private]
bool QgsGeometry::insertVertex ( double  x,
double  y,
int  beforeVertex 
)

Insert a new vertex before the given vertex index, ring and item (first number is index 0) If the requested vertex number (beforeVertex.back()) is greater than the last actual vertex on the requested ring and item, it is assumed that the vertex is to be appended instead of inserted.

Returns false if atVertex does not correspond to a valid vertex on this geometry (including if this geometry is a Point). It is up to the caller to distinguish between these error conditions. (Or maybe we add another method to this object to help make the distinction?)

Definition at line 1835 of file qgsgeometry.cpp.

References exportGeosToWkb(), mDirtyGeos, mDirtyWkb, mGeometry, mGeometrySize, QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBNoGeometry, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, wkbType(), and QGis::WKBUnknown.

Referenced by QgsVectorLayer::insertVertex().

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

Insert a new vertex before the given vertex index (first number is index 0) in the given GEOS Coordinate Sequence.

If the requested vertex number is greater than the last actual vertex, it is assumed that the vertex is to be appended instead of inserted.

Parameters:
xx coordinate
yy coordinate
beforeVertexinsert before vertex with this index
old_sequenceThe sequence to update (The caller remains the owner).
new_sequenceThe updated sequence (The caller becomes the owner if the function returns true). Returns false if beforeVertex does not correspond to a valid vertex number on the Coordinate Sequence.

Definition at line 1205 of file qgsgeometry.cpp.

Returns a geometry representing the points shared by this geometry and other.

Definition at line 6412 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

Referenced by QgsOverlayAnalyzer::intersectFeature(), QgsPalLayerSettings::registerFeature(), and QgsZonalStatistics::statisticsFromPreciseIntersection().

Test for intersection with a rectangle (uses GEOS)

Definition at line 3801 of file qgsgeometry.cpp.

References fromRect().

Referenced by QgsOverlayAnalyzer::intersectFeature().

bool QgsGeometry::intersects ( QgsGeometry geometry)

Test for intersection with a geometry (uses GEOS)

Definition at line 3809 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), mGeos, and QgsDebugMsg.

check if geometry is empty using GEOS

Note:
added in 1.5

Definition at line 6748 of file qgsgeometry.cpp.

References asGeos(), QgsMessageLog::logMessage(), and GEOSException::what().

compare geometries using GEOS

Note:
added in 1.5

Definition at line 6743 of file qgsgeometry.cpp.

References geosRelOp().

Referenced by QgsVectorLayer::updateFeature().

check validity using GEOS

Note:
added in 1.5

Definition at line 6725 of file qgsgeometry.cpp.

References asGeos(), QgsMessageLog::logMessage(), and GEOSException::what().

double QgsGeometry::leftOf ( double  x,
double  y,
double &  x1,
double &  y1,
double &  x2,
double &  y2 
) [private]

Returns < 0 if point(x/y) is left of the line x1,y1 -> x1,y2.

Definition at line 6766 of file qgsgeometry.cpp.

Referenced by closestSegmentWithContext().

double QgsGeometry::length ( )

get length of geometry using GEOS

Note:
added in 1.5

Definition at line 6297 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), and mGeos.

Referenced by QgsPalLayerSettings::checkMinimumSizeMM(), and fromWkb().

int QgsGeometry::lineContainedInLine ( const GEOSGeometry *  line1,
const GEOSGeometry *  line2 
) [static, private]

Tests if line1 is completely contained in line2.

This method works with a very small buffer around line2 and therefore is less prone to numerical errors as the corresponding geos method

Definition at line 5891 of file qgsgeometry.cpp.

References DEFAULT_QUADRANT_SEGMENTS, and geomInDegrees().

Referenced by reshapeLine(), and splitLinearGeometry().

Changes this geometry such that it does not intersect the other geometry.

Parameters:
othergeometry that should not be intersect
Returns:
0 in case of success

Definition at line 3456 of file qgsgeometry.cpp.

References CATCH_GEOS, convertToMultiType(), exportWkbToGeos(), isMultipart(), mDirtyGeos, mDirtyWkb, and mGeos.

Referenced by QgsVectorLayer::removePolygonIntersections().

int QgsGeometry::mergeGeometriesMultiTypeSplit ( QVector< GEOSGeometry * > &  splitResult) [private]
bool QgsGeometry::moveVertex ( double  x,
double  y,
int  atVertex 
)

Moves the vertex at the given position number and item (first number is index 0) to the given coordinates.

Returns false if atVertex does not correspond to a valid vertex on this geometry

Definition at line 1257 of file qgsgeometry.cpp.

References exportGeosToWkb(), mDirtyGeos, mDirtyWkb, mGeometry, QgsDebugMsg, QGis::WKBLineString, QGis::WKBLineString25D, QGis::WKBMultiLineString, QGis::WKBMultiLineString25D, QGis::WKBMultiPoint, QGis::WKBMultiPoint25D, QGis::WKBMultiPolygon, QGis::WKBMultiPolygon25D, QGis::WKBPoint, QGis::WKBPoint25D, QGis::WKBPolygon, QGis::WKBPolygon25D, and wkbType().

Referenced by QgsVectorLayer::moveVertex().

GEOSGeometry * QgsGeometry::nodeGeometries ( const GEOSGeometry *  splitLine,
const GEOSGeometry *  poly 
) [static, private]

Nodes together a split line and a (multi-) polygon geometry in a multilinestring.

Returns:
the noded multiline geometry or 0 in case of error. The calling function takes ownership of the node geometry

Definition at line 5866 of file qgsgeometry.cpp.

Referenced by reshapeLine(), splitLinearGeometry(), and splitPolygonGeometry().

int QgsGeometry::numberOfGeometries ( GEOSGeometry *  g) const [private]

Returns number of single geometry in a geos geometry.

Is save for geos 2 and 3

Definition at line 6002 of file qgsgeometry.cpp.

Referenced by splitPolygonGeometry().

QgsGeometry & QgsGeometry::operator= ( QgsGeometry const &  rhs)

assignments will prompt a deep copy of the object

Definition at line 530 of file qgsgeometry.cpp.

References mDirtyGeos, mDirtyWkb, mGeometry, mGeometrySize, and mGeos.

bool QgsGeometry::overlaps ( QgsGeometry geometry)

Test for if geometry overlaps an other (uses GEOS)

Note:
added in 1.5

Definition at line 3901 of file qgsgeometry.cpp.

References geosRelOp().

int QgsGeometry::pointContainedInLine ( const GEOSGeometry *  point,
const GEOSGeometry *  line 
) [static, private]

Tests if a point is on a line.

This method works with a very small buffer and is thus less prone to numerical problems as the direct geos functions.

Parameters:
pointthe point to test
lineline to test
Returns:
0 not contained, 1 if contained, <0 in case of error

Definition at line 5930 of file qgsgeometry.cpp.

References geomInDegrees().

Referenced by reshapeLine().

int QgsGeometry::reshapeGeometry ( const QList< QgsPoint > &  reshapeWithLine)

Replaces a part of this geometry with another line.

Returns:
0 in case of success
Note:
: this function was added in version 1.3

Definition at line 3332 of file qgsgeometry.cpp.

References createGeosLineString(), exportWkbToGeos(), QGis::Line, mDirtyGeos, mDirtyWkb, mGeos, QGis::Point, reshapeLine(), reshapePolygon(), and type().

GEOSGeometry * QgsGeometry::reshapeLine ( const GEOSGeometry *  origLine,
const GEOSGeometry *  reshapeLineGeos 
) [static, private]

Creates a new line from an original line and a reshape line.

The part of the input line from the first to the last intersection with the reshape line will be replaced. The calling function takes ownership of the result.

Parameters:
origLinethe original line
reshapeLineGeosthe reshape line
Returns:
the reshaped line or 0 in case of error

Definition at line 5562 of file qgsgeometry.cpp.

References createGeosPoint(), lineContainedInLine(), QgsMessageLog::logMessage(), nodeGeometries(), pointContainedInLine(), and GEOSException::what().

Referenced by reshapeGeometry(), and reshapePolygon().

GEOSGeometry * QgsGeometry::reshapePolygon ( const GEOSGeometry *  polygon,
const GEOSGeometry *  reshapeLineGeos 
) [static, private]

Creates a new polygon replacing the part from the first to the second intersection with the reshape line.

As a polygon ring is always closed, the method keeps the longer part of the existing boundary

Parameters:
polygongeometry to reshape
reshapeLineGeosthe reshape line
Returns:
the reshaped polygon or 0 in case of error

Definition at line 5429 of file qgsgeometry.cpp.

References QgsMessageLog::logMessage(), reshapeLine(), and GEOSException::what().

Referenced by reshapeGeometry().

QgsGeometry * QgsGeometry::simplify ( double  tolerance)

Returns a simplified version of this geometry using a specified tolerance value.

Definition at line 6360 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

Referenced by QgsGeometryAnalyzer::simplifyFeature().

int QgsGeometry::splitGeometry ( const QList< QgsPoint > &  splitLine,
QList< QgsGeometry * > &  newGeometries,
bool  topological,
QList< QgsPoint > &  topologyTestPoints 
)

Splits this geometry according to a given line.

Note that the geometry is only split once. If there are several intersections between geometry and splitLine, only the first one is considered.

Parameters:
splitLinethe line that splits the geometry
[out]newGeometrieslist of new geometries that have been created with the split
topologicaltrue if topological editing is enabled
[out]topologyTestPointspoints that need to be tested for topological completeness in the dataset
Returns:
0 in case of success, 1 if geometry has not been split, error else

Definition at line 3257 of file qgsgeometry.cpp.

References CATCH_GEOS, createGeosLineString(), exportGeosToWkb(), exportWkbToGeos(), QGis::Line, mDirtyGeos, mDirtyWkb, mGeos, QGis::Point, QGis::Polygon, splitLinearGeometry(), splitPolygonGeometry(), topologicalTestPointsSplit(), and type().

Referenced by QgsVectorLayer::splitFeatures().

int QgsGeometry::splitLinearGeometry ( GEOSGeometry *  splitLine,
QList< QgsGeometry * > &  newGeometries 
) [private]

Splits line/multiline geometries.

Parameters:
splitLinethe line that splits the feature
newGeometriesnew geometries if splitting was successful
Returns:
0 in case of success, 1 if geometry has not been split, error else

Definition at line 5248 of file qgsgeometry.cpp.

References exportWkbToGeos(), fromGeosGeom(), lineContainedInLine(), mDirtyGeos, mDirtyWkb, mergeGeometriesMultiTypeSplit(), mGeos, and nodeGeometries().

Referenced by splitGeometry().

int QgsGeometry::splitPolygonGeometry ( GEOSGeometry *  splitLine,
QList< QgsGeometry * > &  newGeometries 
) [private]

Splits polygon/multipolygon geometries.

Returns:
0 in case of success, 1 if geometry has not been split, error else

Definition at line 5309 of file qgsgeometry.cpp.

References exportWkbToGeos(), fromGeosGeom(), mDirtyGeos, mDirtyWkb, mergeGeometriesMultiTypeSplit(), mGeos, nodeGeometries(), numberOfGeometries(), and QgsDebugMsg.

Referenced by splitGeometry().

double QgsGeometry::sqrDistToVertexAt ( QgsPoint point,
int  atVertex 
)

Returns the squared cartesian distance between the given point to the given vertex index (vertex at the given position number, ring and item (first number is index 0))

Definition at line 2343 of file qgsgeometry.cpp.

References MathUtils::max(), QgsDebugMsg, QgsPoint::sqrDist(), QgsPoint::toString(), and vertexAt().

Returns a Geometry representing the points making up this Geometry that do not make up other.

Definition at line 6500 of file qgsgeometry.cpp.

References CATCH_GEOS, exportWkbToGeos(), fromGeosGeom(), and mGeos.

int QgsGeometry::topologicalTestPointsSplit ( const GEOSGeometry *  splitLine,
QList< QgsPoint > &  testPoints 
) const [private]

Finds out the points that need to be tested for topological correctnes if this geometry will be split.

Returns:
0 in case of success

Definition at line 5808 of file qgsgeometry.cpp.

References mGeos.

Referenced by splitGeometry().

bool QgsGeometry::touches ( QgsGeometry geometry)

Test for if geometry touch an other (uses GEOS)

Note:
added in 1.5

Definition at line 3896 of file qgsgeometry.cpp.

References geosRelOp().

void QgsGeometry::transformVertex ( int &  wkbPosition,
const QgsCoordinateTransform ct,
bool  hasZValue 
) [private]

Transforms a single vertex by ct.

Parameters:
wkbPositionposition in wkb array. Is increased automatically by the function
ctthe QgsCoordinateTransform
hasZValue25D type?

Definition at line 5223 of file qgsgeometry.cpp.

References mGeometry, and QgsCoordinateTransform::transformInPlace().

Referenced by transform().

int QgsGeometry::translate ( double  dx,
double  dy 
)
void QgsGeometry::translateVertex ( int &  wkbPosition,
double  dx,
double  dy,
bool  hasZValue 
) [private]

Translates a single vertex by dx and dy.

Parameters:
wkbPositionposition in wkb array. Is increased automatically by the function
dxtranslation of x-coordinate
dytranslation of y-coordinate
hasZValue25D type?

Definition at line 5201 of file qgsgeometry.cpp.

References mGeometry.

Referenced by translate().

void QgsGeometry::validateGeometry ( QList< Error > &  errors)

Validate geometry and produce a list of geometry errors.

Note:
added in 1.5

Definition at line 6720 of file qgsgeometry.cpp.

QgsPoint QgsGeometry::vertexAt ( int  atVertex)
bool QgsGeometry::within ( QgsGeometry geometry)

Test for if geometry is within an other (uses GEOS)

Note:
added in 1.5

Definition at line 3906 of file qgsgeometry.cpp.

References geosRelOp().

Returns the size of the WKB in asWkb().

Definition at line 595 of file qgsgeometry.cpp.

References exportGeosToWkb(), mDirtyWkb, and mGeometrySize.

Referenced by QgsVectorFileWriter::addFeature(), QgsGeometryAnalyzer::dissolveFeature(), and QgsLabel::labelPoint().


Member Data Documentation

bool QgsGeometry::mDirtyGeos [private]
bool QgsGeometry::mDirtyWkb [private]
unsigned char* QgsGeometry::mGeometry [private]
size_t QgsGeometry::mGeometrySize [private]

size of geometry

Definition at line 459 of file qgsgeometry.h.

Referenced by convertToMultiType(), deleteVertex(), exportGeosToWkb(), fromWkb(), insertVertex(), operator=(), QgsGeometry(), and wkbSize().

GEOSGeometry* QgsGeometry::mGeos [private]
int QgsGeometry::refcount [static, private]

Definition at line 580 of file qgsgeometry.h.


The documentation for this class was generated from the following files:
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