qgsdistancearea.h

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/***************************************************************************
  qgsdistancearea.h - Distance and area calculations on the ellipsoid
 ---------------------------------------------------------------------------
  Date                 : September 2005
  Copyright            : (C) 2005 by Martin Dobias
  email                : won.der at centrum.sk
 ***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSDISTANCEAREA_H
#define QGSDISTANCEAREA_H
 
#include "qgis_core.h"
#include <QVector>
#include <QReadWriteLock>
#include "qgscoordinatetransform.h"
#include "qgsunittypes.h"
#include "qgsellipsoidutils.h"
 
class QgsGeometry;
class QgsAbstractGeometry;
class QgsCurve;
 
class CORE_EXPORT QgsDistanceArea
{
  public:
 
    QgsDistanceArea();
 
    bool willUseEllipsoid() const;
 
    void setSourceCrs( const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context );
 
    QgsCoordinateReferenceSystem sourceCrs() const { return mCoordTransform.sourceCrs(); }
 
    QgsCoordinateReferenceSystem ellipsoidCrs() const { return mCoordTransform.destinationCrs(); }
 
    bool setEllipsoid( const QString &ellipsoid );
 
    bool setEllipsoid( double semiMajor, double semiMinor );
 
    QString ellipsoid() const { return mEllipsoid; }
 
    double ellipsoidSemiMajor() const { return mSemiMajor; }
 
    double ellipsoidSemiMinor() const { return mSemiMinor; }
 
    double ellipsoidInverseFlattening() const { return mInvFlattening; }
 
    double measureArea( const QgsGeometry &geometry ) const;
 
    double measureLength( const QgsGeometry &geometry ) const;
 
    double measurePerimeter( const QgsGeometry &geometry ) const;
 
    double measureLine( const QVector<QgsPointXY> &points ) const;
 
    double measureLine( const QgsPointXY &p1, const QgsPointXY &p2 ) const;
 
    double measureLineProjected( const QgsPointXY &p1, double distance = 1, double azimuth = M_PI_2, QgsPointXY *projectedPoint SIP_OUT = nullptr ) const;
 
    QgsUnitTypes::DistanceUnit lengthUnits() const;
 
    QgsUnitTypes::AreaUnit areaUnits() const;
 
    double measurePolygon( const QVector<QgsPointXY> &points ) const;
 
    double bearing( const QgsPointXY &p1, const QgsPointXY &p2 ) const;
 
    static QString formatDistance( double distance, int decimals, QgsUnitTypes::DistanceUnit unit, bool keepBaseUnit = false );
 
    static QString formatArea( double area, int decimals, QgsUnitTypes::AreaUnit unit, bool keepBaseUnit = false );
 
    double convertLengthMeasurement( double length, QgsUnitTypes::DistanceUnit toUnits ) const;
 
    double convertAreaMeasurement( double area, QgsUnitTypes::AreaUnit toUnits ) const;
 
    QgsPointXY computeSpheroidProject( const QgsPointXY &p1, double distance = 1, double azimuth = M_PI_2 ) const;
 
    QVector<QVector<QgsPointXY> > geodesicLine( const QgsPointXY &p1, const QgsPointXY &p2, double interval, bool breakLine = false ) const;
 
    double latitudeGeodesicCrossesAntimeridian( const QgsPointXY &p1, const QgsPointXY &p2, double &fractionAlongLine SIP_OUT ) const;
 
    QgsGeometry splitGeometryAtAntimeridian( const QgsGeometry &geometry ) const;
 
  private:
 
    double computeDistanceBearing( const QgsPointXY &p1, const QgsPointXY &p2,
                                   double *course1 = nullptr, double *course2 = nullptr ) const;
 
    double computePolygonArea( const QVector<QgsPointXY> &points ) const;
 
    double computePolygonFlatArea( const QVector<QgsPointXY> &points ) const;
 
    void computeAreaInit();
 
    void setFromParams( const QgsEllipsoidUtils::EllipsoidParameters &params );
 
    enum MeasureType
    {
      Default,
      Area,
      Length
    };
 
    QgsCoordinateTransform mCoordTransform;
 
    QString mEllipsoid;
 
    double mSemiMajor, mSemiMinor, mInvFlattening;
 
    // utility functions for polygon area measurement
 
    double getQ( double x ) const;
    double getQbar( double x ) const;
 
    double measure( const QgsAbstractGeometry *geomV2, MeasureType type = Default ) const;
    double measureLine( const QgsCurve *curve ) const;
    double measurePolygon( const QgsCurve *curve ) const;
 
    // temporary area measurement stuff
 
    double m_QA, m_QB, m_QC;
    double m_QbarA, m_QbarB, m_QbarC, m_QbarD;
    double m_AE;  /* a^2(1-e^2) */
    double m_Qp;  /* Q at the north pole */
    double m_E;   /* area of the earth */
    double m_TwoPI;
 
};
 
#endif