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.h"
#include "qgis_core.h"
#include "qgscoordinatetransform.h"
#include "qgsellipsoidutils.h"
 
#include <QReadWriteLock>
#include <QVector>
 
class QgsGeometry;
class QgsAbstractGeometry;
class QgsCurve;
struct geod_geodesic;

class CORE_EXPORT QgsDistanceArea
{
  public:
    QgsDistanceArea();
    ~QgsDistanceArea();
 
    QgsDistanceArea( const QgsDistanceArea &other );
    SIP_SKIP QgsDistanceArea( QgsDistanceArea &&other );
    QgsDistanceArea &operator=( const QgsDistanceArea &other );
    QgsDistanceArea &operator=( QgsDistanceArea &&other );

    bool willUseEllipsoid() const;

    void setSourceCrs( const QgsCoordinateReferenceSystem &crs, const QgsCoordinateTransformContext &context );

    QgsCoordinateReferenceSystem sourceCrs() const { return sourceToEllipsoid().sourceCrs(); }

    QgsCoordinateReferenceSystem ellipsoidCrs() const { return sourceToEllipsoid().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 SIP_THROW( QgsCsException );

    double measureLength( const QgsGeometry &geometry ) const SIP_THROW( QgsCsException );

    double measurePerimeter( const QgsGeometry &geometry ) const SIP_THROW( QgsCsException );

    double measureLine( const QVector<QgsPointXY> &points ) const SIP_THROW( QgsCsException );

    double measureLine( const QgsPointXY &p1, const QgsPointXY &p2 ) const SIP_THROW( QgsCsException );

    double measureLineProjected( const QgsPointXY &p1, double distance = 1, double azimuth = M_PI_2, QgsPointXY *projectedPoint SIP_OUT = nullptr ) const;

    Qgis::DistanceUnit lengthUnits() const;

    Qgis::AreaUnit areaUnits() const;

    double measurePolygon( const QVector<QgsPointXY> &points ) const SIP_THROW( QgsCsException );

    double bearing( const QgsPointXY &p1, const QgsPointXY &p2 ) const SIP_THROW( QgsCsException );

    static QString formatDistance( double distance, int decimals, Qgis::DistanceUnit unit, bool keepBaseUnit = false );

    static QString formatArea( double area, int decimals, Qgis::AreaUnit unit, bool keepBaseUnit = false );

    double convertLengthMeasurement( double length, Qgis::DistanceUnit toUnits ) const;

    double convertAreaMeasurement( double area, Qgis::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:
    // Calculates area of polygon on ellipsoid
    double computePolygonArea( const QVector<QgsPointXY> &points ) const;
 
    double computePolygonFlatArea( const QVector<QgsPointXY> &points ) const;

    void computeAreaInit() const;
 
    void setFromParams( const QgsEllipsoidUtils::EllipsoidParameters &params );
 
    enum MeasureType
    {
      Default,
      Area,
      Length
    };

    mutable QgsCoordinateTransform mCachedSourceToEllipsoid;

    QString mEllipsoid;

    double mSemiMajor, mSemiMinor, mInvFlattening;
 
    mutable std::unique_ptr< geod_geodesic > mGeod;
 
    QgsCoordinateReferenceSystem mDestinationCrs; // the ellipsoid CRS, which is the destination CRS for mCachedSourceToEllipsoid
    QgsCoordinateReferenceSystem mSourceCrs;
    QgsCoordinateTransformContext mCoordTransformContext;
 
    mutable bool mCoordTransformDirty = false;
 
    // utility functions for polygon area measurement
 
    double measure( const QgsAbstractGeometry *geomV2, MeasureType type = Default ) const;
    double measureLine( const QgsCurve *curve ) const;
    double measurePolygon( const QgsCurve *curve ) const;
 
    QgsCoordinateTransform sourceToEllipsoid() const;
 
    friend class TestQgsDistanceArea;
};
 
#endif