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00018 #include "qgstotalcurvaturefilter.h"
00019
00020 QgsTotalCurvatureFilter::QgsTotalCurvatureFilter( const QString& inputFile, const QString& outputFile, const QString& outputFormat ): \
00021 QgsNineCellFilter( inputFile, outputFile, outputFormat )
00022 {
00023
00024 }
00025
00026 QgsTotalCurvatureFilter::~QgsTotalCurvatureFilter()
00027 {
00028
00029 }
00030
00031 float QgsTotalCurvatureFilter::processNineCellWindow( float* x11, float* x21, float* x31, float* x12, \
00032 float* x22, float* x32, float* x13, float* x23, float* x33 )
00033 {
00034
00035 if ( *x11 == mInputNodataValue || *x21 == mInputNodataValue || *x31 == mInputNodataValue || *x12 == mInputNodataValue \
00036 || *x22 == mInputNodataValue || *x32 == mInputNodataValue || *x13 == mInputNodataValue || *x23 == mInputNodataValue \
00037 || *x33 == mInputNodataValue )
00038 {
00039 return mOutputNodataValue;
00040 }
00041
00042 double cellSizeAvg = ( mCellSizeX + mCellSizeY ) / 2.0;
00043 double dxx = ( *x32 - 2 * *x22 + *x12 ) / ( mCellSizeX * mCellSizeX );
00044 double dyy = ( -*x11 + *x31 + *x13 - *x33 ) / ( 4 * cellSizeAvg * cellSizeAvg );
00045 double dxy = ( *x21 - 2 * *x22 + *x23 ) / ( mCellSizeY * mCellSizeY );
00046
00047 return dxx*dxx + 2*dxy*dxy + dyy*dyy;
00048 }