Small optimisation for zstats so that we dont do more expensive geoemtry operation when we know that cell value is null already.

Author: timlinux

src/analysis/vector/qgszonalstatistics.cpp

@@ -306,9 +306,9 @@ void QgsZonalStatistics::statisticsFromMiddlePointTest( void* band, QgsGeometry*
       GEOSCoordSeq_setY( cellCenterCoords, 0, cellCenterY );
       currentCellCenter = GEOSGeom_createPoint( cellCenterCoords );
 
-      if ( GEOSPreparedContains( polyGeosPrepared, currentCellCenter ) )
+      if ( scanLine[j] != mInputNodataValue ) //don't consider nodata values
       {
-        if ( scanLine[j] != mInputNodataValue ) //don't consider nodata values
+        if ( GEOSPreparedContains( polyGeosPrepared, currentCellCenter ) )
         {
           sum += scanLine[j];
           ++count;