double QgsDistanceArea::measureLine( const QgsPoint &p1, const QgsPoint &p2 ) const
{
double result;
try
{
QgsPoint pp1 = p1, pp2 = p2;
QgsDebugMsgLevel( QString( "Measuring from %1 to %2" ).arg( p1.toString( 4 ), p2.toString( 4 ) ), 3 );
if ( mEllipsoidalMode && ( mEllipsoid != GEO_NONE ) )
{
QgsDebugMsgLevel( QString( "Ellipsoidal calculations is enabled, using ellipsoid %1" ).arg( mEllipsoid ), 4 );
QgsDebugMsgLevel( QString( "From proj4 : %1" ).arg( mCoordTransform->sourceCrs().toProj4() ), 4 );
QgsDebugMsgLevel( QString( "To proj4 : %1" ).arg( mCoordTransform->destCRS().toProj4() ), 4 );
pp1 = mCoordTransform->transform( p1 );
pp2 = mCoordTransform->transform( p2 );
QgsDebugMsgLevel( QString( "New points are %1 and %2, calculating..." ).arg( pp1.toString( 4 ), pp2.toString( 4 ) ), 4 );
result = computeDistanceBearing( pp1, pp2 );
}
else
{
QgsDebugMsgLevel( "Cartesian calculation on canvas coordinates", 4 );
result = computeDistanceFlat( p1, p2 );
}
}
catch ( QgsCsException &cse )
{
Q_UNUSED( cse );
QgsMessageLog::logMessage( QObject::tr( "Caught a coordinate system exception while trying to transform a point. Unable to calculate line length." ) );
result = 0.0;
}
QgsDebugMsgLevel( QString( "The result was %1" ).arg( result ), 3 );
return result;
}
double QgsDistanceArea::computeDistance( const QList<QgsPoint>& points ) const
{
if ( points.size() < 2 )
return 0;
double total = 0;
QgsPoint p1, p2;
try
{
p1 = points[0];
for ( QList<QgsPoint>::const_iterator i = points.begin(); i != points.end(); ++i )
{
p2 = *i;
if ( mEllipsoidalMode && ( mEllipsoid != GEO_NONE ) )
{
total += computeDistanceBearing( p1, p2 );
}
else
{
total += computeDistanceFlat( p1, p2 );
}
p1 = p2;
}
return total;
}
catch ( QgsCsException &cse )
{
Q_UNUSED( cse );
QgsMessageLog::logMessage( QObject::tr( "Caught a coordinate system exception while trying to transform a point. Unable to calculate line length." ) );
return 0.0;
}
}
