void TestQgsDistanceArea::measureAreaAndUnits()
{
QgsDistanceArea da;
da.setSourceCrs( 3452 );
da.setEllipsoidalMode( false );
da.setEllipsoid( "NONE" );
QgsCoordinateReferenceSystem daCRS;
daCRS.createFromSrsId( da.sourceCrsId() );
QgsPolyline ring;
ring << QgsPoint( 0, 0 )
<< QgsPoint( 1, 0 )
<< QgsPoint( 1, 1 )
<< QgsPoint( 2, 1 )
<< QgsPoint( 2, 2 )
<< QgsPoint( 0, 2 )
<< QgsPoint( 0, 0 );
QgsPolygon poly;
poly << ring;
QgsGeometry polygon( QgsGeometry::fromPolygon( poly ) );
// We check both the measured area AND the units, in case the logic regarding
// ellipsoids and units changes in future
double area = da.measureArea( &polygon );
QgsUnitTypes::AreaUnit units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QVERIFY(( qgsDoubleNear( area, 3.0, 0.00000001 ) && units == QgsUnitTypes::AreaSquareDegrees )
|| ( qgsDoubleNear( area, 37176087091.5, 0.1 ) && units == QgsUnitTypes::AreaSquareMeters ) );
da.setEllipsoid( "WGS84" );
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QVERIFY(( qgsDoubleNear( area, 3.0, 0.00000001 ) && units == QgsUnitTypes::AreaSquareDegrees )
|| ( qgsDoubleNear( area, 37176087091.5, 0.1 ) && units == QgsUnitTypes::AreaSquareMeters ) );
da.setEllipsoidalMode( true );
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
// should always be in Meters Squared
QGSCOMPARENEAR( area, 37416879192.9, 0.1 );
QCOMPARE( units, QgsUnitTypes::AreaSquareMeters );
// test converting the resultant area
area = da.convertAreaMeasurement( area, QgsUnitTypes::AreaSquareMiles );
QGSCOMPARENEAR( area, 14446.7378, 0.001 );
// now try with a source CRS which is in feet
ring.clear();
ring << QgsPoint( 1850000, 4423000 )
<< QgsPoint( 1851000, 4423000 )
<< QgsPoint( 1851000, 4424000 )
<< QgsPoint( 1852000, 4424000 )
<< QgsPoint( 1852000, 4425000 )
<< QgsPoint( 1851000, 4425000 )
<< QgsPoint( 1850000, 4423000 );
poly.clear();
poly << ring;
polygon = QgsGeometry::fromPolygon( poly );
da.setSourceCrs( 27469 );
da.setEllipsoidalMode( false );
// measurement should be in square feet
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QGSCOMPARENEAR( area, 2000000, 0.001 );
QCOMPARE( units, QgsUnitTypes::AreaSquareFeet );
// test converting the resultant area
area = da.convertAreaMeasurement( area, QgsUnitTypes::AreaSquareYards );
QGSCOMPARENEAR( area, 222222.2222, 0.001 );
da.setEllipsoidalMode( true );
// now should be in Square Meters again
area = da.measureArea( &polygon );
units = da.areaUnits();
QgsDebugMsg( QString( "measured %1 in %2" ).arg( area ).arg( QgsUnitTypes::toString( units ) ) );
QGSCOMPARENEAR( area, 184149.37, 1.0 );
QCOMPARE( units, QgsUnitTypes::AreaSquareMeters );
// test converting the resultant area
area = da.convertAreaMeasurement( area, QgsUnitTypes::AreaSquareYards );
QgsDebugMsg( QString( "measured %1 in sq yrds" ).arg( area ) );
QGSCOMPARENEAR( area, 220240.8172549, 0.00001 );
}
