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Fix calculation of zonal stats when source contains nodata or nan

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pixels (fix #11135)
This commit is contained in:
Nyall Dawson 2015-04-16 21:17:23 +10:00
parent 6a46f464f7
commit 213a22bc8a
2 changed files with 24 additions and 11 deletions
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21
src/analysis/vector/qgszonalstatistics.cpp
View File

@ -301,21 +301,17 @@ void QgsZonalStatistics::statisticsFromMiddlePointTest( void* band, QgsGeometry*
}
cellCenterX = rasterBBox.xMinimum() + pixelOffsetX * cellSizeX + cellSizeX / 2;
for ( int j = 0; j < nCellsX; ++j )
{
if ( validPixel( scanLine[j] ) )
{
GEOSGeom_destroy_r( geosctxt, currentCellCenter );
cellCenterCoords = GEOSCoordSeq_create_r( geosctxt, 1, 2 );
GEOSCoordSeq_setX_r( geosctxt, cellCenterCoords, 0, cellCenterX );
GEOSCoordSeq_setY_r( geosctxt, cellCenterCoords, 0, cellCenterY );
currentCellCenter = GEOSGeom_createPoint_r( geosctxt, cellCenterCoords );
if ( scanLine[j] != mInputNodataValue ) //don't consider nodata values
{
if ( GEOSPreparedContains_r( geosctxt, polyGeosPrepared, currentCellCenter ) )
{
if ( !qIsNaN( scanLine[j] ) )
{
sum += scanLine[j];
}
++count;
}
}
@ -323,6 +319,7 @@ void QgsZonalStatistics::statisticsFromMiddlePointTest( void* band, QgsGeometry*
}
cellCenterY -= cellSizeY;
}
GEOSGeom_destroy_r( geosctxt, currentCellCenter );
CPLFree( scanLine );
GEOSPreparedGeom_destroy_r( geosctxt, polyGeosPrepared );
}
@ -347,6 +344,9 @@ void QgsZonalStatistics::statisticsFromPreciseIntersection( void* band, QgsGeome
for ( int col = 0; col < nCellsX; ++col )
{
GDALRasterIO( band, GF_Read, pixelOffsetX + col, pixelOffsetY + row, nCellsX, 1, pixelData, 1, 1, GDT_Float32, 0, 0 );
if ( !validPixel( *pixelData ) )
continue;
pixelRectGeometry = QgsGeometry::fromRect( QgsRectangle( currentX - hCellSizeX, currentY - hCellSizeY, currentX + hCellSizeX, currentY + hCellSizeY ) );
if ( pixelRectGeometry )
{
@ -373,6 +373,15 @@ void QgsZonalStatistics::statisticsFromPreciseIntersection( void* band, QgsGeome
CPLFree( pixelData );
}
bool QgsZonalStatistics::validPixel( float value ) const
{
if ( value == mInputNodataValue || qIsNaN( value ) )
{
return false;
}
return true;
}
QString QgsZonalStatistics::getUniqueFieldName( QString fieldName )
{
QgsVectorDataProvider* dp = mPolygonLayer->dataProvider();

4
src/analysis/vector/qgszonalstatistics.h
View File

@ -54,6 +54,9 @@ class ANALYSIS_EXPORT QgsZonalStatistics
void statisticsFromPreciseIntersection( void* band, QgsGeometry* poly, int pixelOffsetX, int pixelOffsetY, int nCellsX, int nCellsY,
double cellSizeX, double cellSizeY, const QgsRectangle& rasterBBox, double& sum, double& count );
/**Tests whether a pixel's value should be included in the result*/
bool validPixel( float value ) const;
QString getUniqueFieldName( QString fieldName );
QString mRasterFilePath;
@ -63,6 +66,7 @@ class ANALYSIS_EXPORT QgsZonalStatistics
QString mAttributePrefix;
/**The nodata value of the input layer*/
float mInputNodataValue;
};
#endif // QGSZONALSTATISTICS_H