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Merge pull request #62212 from elpaso/bugfix-gh61299-ellipsoidal-distance-custom-proj2

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Fix distance calculation with custom projection
This commit is contained in:
Alessandro Pasotti 2025-06-12 07:29:59 +02:00 committed by GitHub
commit ec8680e666
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GPG Key ID: B5690EEEBB952194
3 changed files with 66 additions and 1 deletions
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1
src/core/proj/qgsellipsoidutils.cpp
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@ -214,6 +214,7 @@ QgsEllipsoidUtils::EllipsoidParameters QgsEllipsoidUtils::ellipsoidParameters( c
params.semiMinor = semiMinor;
params.inverseFlattening = semiMajor / ( semiMajor - semiMinor );
params.useCustomParameters = true;
params.crs.createFromProj( QStringLiteral( "+proj=longlat +a=%1 +b=%2 +no_defs +type=crs" ).arg( params.semiMajor, 0, 'g', 17 ).arg( params.semiMinor, 0, 'g', 17 ) );
}
else
{

1
src/core/qgsdistancearea.cpp
View File

@ -876,6 +876,7 @@ void QgsDistanceArea::setFromParams( const QgsEllipsoidUtils::EllipsoidParameter
if ( params.useCustomParameters )
{
setEllipsoid( params.semiMajor, params.semiMinor );
mCoordTransform.setDestinationCrs( params.crs );
}
else
{

65
tests/src/core/testqgsdistancearea.cpp
View File

@ -46,6 +46,7 @@ class TestQgsDistanceArea : public QObject
void emptyPolygon();
void regression14675();
void regression16820();
void regression61299();
};
void TestQgsDistanceArea::initTestCase()
@ -53,7 +54,7 @@ void TestQgsDistanceArea::initTestCase()
//
// Runs once before any tests are run
//
// init QGIS's paths - true means that all path will be inited from prefix
// init QGIS's paths true means that all path will be inited from prefix
QgsApplication::init();
QgsApplication::initQgis();
QgsApplication::showSettings();
@ -392,5 +393,67 @@ void TestQgsDistanceArea::regression16820()
QGSCOMPARENEAR( calc.measureArea( geom ), 43.201092, 0.001 );
}
void TestQgsDistanceArea::regression61299()
{
// Create custom CRS from WKT
const QgsCoordinateReferenceSystem userCrs = QgsCoordinateReferenceSystem::fromWkt( R"WKT(
PROJCRS["Hanseong PCS",
BASEGEOGCRS["WGS 84",
DATUM["World Geodetic System 1984",
ELLIPSOID["WGS 84",6378137,298.257223563,
LENGTHUNIT["metre",1]],
ID["EPSG",6326]],
PRIMEM["Greenwich",0,
ANGLEUNIT["Degree",0.0174532925199433],
ID["EPSG",8901]]],
CONVERSION["unnamed",
METHOD["Mercator (variant B)",
ID["EPSG",9805]],
PARAMETER["Latitude of 1st standard parallel",37.5,
ANGLEUNIT["Degree",0.0174532925199433],
ID["EPSG",8823]],
PARAMETER["Longitude of natural origin",100,
ANGLEUNIT["Degree",0.0174532925199433],
ID["EPSG",8802]],
PARAMETER["False easting",0,
LENGTHUNIT["metre",1],
ID["EPSG",8806]],
PARAMETER["False northing",0,
LENGTHUNIT["metre",1],
ID["EPSG",8807]]],
CS[Cartesian,2],
AXIS["(E)",east,
ORDER[1],
LENGTHUNIT["metre",1,
ID["EPSG",9001]]],
AXIS["(N)",north,
ORDER[2],
LENGTHUNIT["metre",1,
ID["EPSG",9001]]]]
)WKT" );
QVERIFY( userCrs.isValid() );
QgsProject::instance()->setCrs( userCrs, false );
QgsProject::instance()->setEllipsoid( QStringLiteral( "PARAMETER:6378137:6356752.3142451793" ) );
QgsDistanceArea calc;
QVERIFY( calc.setEllipsoid( QgsProject::instance()->ellipsoid() ) );
calc.setSourceCrs( userCrs, QgsProject::instance()->transformContext() );
QgsPointXY pt1( 110, 38 );
QgsPointXY pt2( 111, 38 );
// Transform to the user CRS
QgsCoordinateTransform transform( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:4326" ) ), userCrs, QgsProject::instance()->transformContext() );
pt1 = transform.transform( pt1 );
pt2 = transform.transform( pt2 );
// This will fail if the ellipsoid is not set correctly
QVERIFY( calc.ellipsoidCrs().isValid() );
const double result = calc.measureLine( pt1, pt2 );
QVERIFY( !std::isnan( result ) );
}
QGSTEST_MAIN( TestQgsDistanceArea )
#include "testqgsdistancearea.moc"