Use the GeographicLib routines exposed through PROJ for all ellipsoidal

calculations Since GRASS upstream is moving away from the previous calculations which all of QGIS' ellipsoidal distance/areas formulas are based on, let's follow suit and delegate all these calculations to the GeographicLib routines exposed through the PROJ api. Refs OSGeo/grass#1283
qgis · Feb 25, 2021 · cc9cbec · cc9cbec
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diff --git a/python/core/auto_generated/qgsdistancearea.sip.in b/python/core/auto_generated/qgsdistancearea.sip.in
@@ -28,6 +28,8 @@ of all measured geometries must first be specified using :py:func:`~setSourceCrs
 Usually, the measurements returned by :py:class:`QgsDistanceArea` are in meters. If no valid
 ellipsoid is set, then the units may not be meters. The units can be retrieved
 by calling :py:func:`~lengthUnits` and :py:func:`~areaUnits`.
+
+Internally, the GeographicLib library is used to calculate all ellipsoid based measurements.
 %End
 
 %TypeHeaderCode
@@ -38,6 +40,12 @@ by calling :py:func:`~lengthUnits` and :py:func:`~areaUnits`.
     QgsDistanceArea();
 %Docstring
 Constructor
+%End
+    ~QgsDistanceArea();
+
+    QgsDistanceArea( const QgsDistanceArea &other );
+%Docstring
+Copy constructor
 %End
 
     bool willUseEllipsoid() const;
@@ -348,26 +356,14 @@ different areal unit.
     QgsPointXY computeSpheroidProject( const QgsPointXY &p1, double distance = 1, double azimuth = M_PI_2 ) const;
 %Docstring
 Given a location, an azimuth and a distance, computes the
-location of the projected point. Based on Vincenty's formula
-for the geodetic direct problem as described in "Geocentric
-Datum of Australia Technical Manual", Chapter 4.
+location of the projected point.
 
 :param p1: - location of first geographic (latitude/longitude) point as degrees.
 :param distance: - distance in meters.
 :param azimuth: - azimuth in radians, clockwise from North
 
 :return: p2 - location of projected point as longitude/latitude.
 
-.. note::
-
-   code (and documentation) taken from rttopo project
-   https://git.osgeo.org/gogs/rttopo/librttopo
-
-- spheroid_project.spheroid_project(...)
-- Valid bounds checking for degrees (latitude=+- 85.05115) is based values used for
--> 'WGS84 Web Mercator (Auxiliary Sphere)' calculations
---> latitudes outside these bounds cause the calculations to become unstable and can return invalid results
-
 .. versionadded:: 3.0
 %End