Quantum GIS API Documentation
1.8
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00001 /*************************************************************************** 00002 qgstotalcurvaturefilter.h - description 00003 ------------------- 00004 begin : August 21th, 2009 00005 copyright : (C) 2009 by Marco Hugentobler 00006 email : marco dot hugentobler at karto dot baug dot ethz dot ch 00007 ***************************************************************************/ 00008 00009 /*************************************************************************** 00010 * * 00011 * This program is free software; you can redistribute it and/or modify * 00012 * it under the terms of the GNU General Public License as published by * 00013 * the Free Software Foundation; either version 2 of the License, or * 00014 * (at your option) any later version. * 00015 * * 00016 ***************************************************************************/ 00017 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 //return nodata if one value is the nodata value 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 }