class QgsDistanceArea
{
%TypeHeaderCode
#include <qgsdistancearea.h>
%End

  public:
    //! Constructor
    QgsDistanceArea();

    //! Destructor
    ~QgsDistanceArea();

    //! Copy constructor
    QgsDistanceArea( const QgsDistanceArea &origDA );

    //! sets whether coordinates must be projected to ellipsoid before measuring
    void setEllipsoidalMode( bool flag );

    //! returns projections enabled flag
    bool ellipsoidalEnabled() const;

    //! sets source spatial reference system (by QGIS CRS)
    void setSourceCrs( long srsid );

    /**
     * Sets source spatial reference system (by QGIS CRS)
     * @note: missing in Python bindings in QGIS < 2.2
     */
    void setSourceCrs( const QgsCoordinateReferenceSystem& srcCRS );

    //! sets source spatial reference system by authid
    void setSourceAuthId( QString authid );

    //! returns source spatial reference system
    long sourceCrs() const;
    //! What sort of coordinate system is being used?
    bool geographic() const;

    //! sets ellipsoid by its acronym
    bool setEllipsoid( const QString& ellipsoid );

    //! Sets ellipsoid by supplied radii
    // Inverse flattening is calculated with invf = a/(a-b)
    bool setEllipsoid( double semiMajor, double semiMinor );

    //! returns ellipsoid's acronym
    const QString& ellipsoid() const;

    //! returns ellipsoid's semi major axis
    double ellipsoidSemiMajor() const;
    //! returns ellipsoid's semi minor axis
    double ellipsoidSemiMinor() const;
    //! returns ellipsoid's inverse flattening
    double ellipsoidInverseFlattening() const;

    //! general measurement (line distance or polygon area)
    double measure( QgsGeometry* geometry );

    //! measures perimeter of polygon
    double measurePerimeter( QgsGeometry* geometry );

    //! measures line
    double measureLine( const QList<QgsPoint>& points );

    //! measures line with one segment
    double measureLine( const QgsPoint& p1, const QgsPoint& p2 );

    //! measures polygon area
    double measurePolygon( const QList<QgsPoint>& points );

    //! compute bearing - in radians
    double bearing( const QgsPoint& p1, const QgsPoint& p2 );

    static QString textUnit( double value, int decimals, QGis::UnitType u, bool isArea, bool keepBaseUnit = false );

    //! Helper for conversion between physical units
    void convertMeasurement( double &measure /In,Out/, QGis::UnitType &measureUnits /In,Out/, QGis::UnitType displayUnits, bool isArea );

};