Quantum GIS API Documentation
1.7.4
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Calculates aspect values in a window of 3x3 cells based on first order derivatives in x- and y- directions. More...
#include <qgsaspectfilter.h>
Public Member Functions | |
QgsAspectFilter (const QString &inputFile, const QString &outputFile, const QString &outputFormat) | |
~QgsAspectFilter () | |
Protected Member Functions | |
float | processNineCellWindow (float *x11, float *x21, float *x31, float *x12, float *x22, float *x32, float *x13, float *x23, float *x33) |
Calculates output value from nine input values. |
Calculates aspect values in a window of 3x3 cells based on first order derivatives in x- and y- directions.
Direction is clockwise starting from north
Definition at line 24 of file qgsaspectfilter.h.
QgsAspectFilter::QgsAspectFilter | ( | const QString & | inputFile, |
const QString & | outputFile, | ||
const QString & | outputFormat | ||
) |
Definition at line 20 of file qgsaspectfilter.cpp.
Definition at line 26 of file qgsaspectfilter.cpp.
float QgsAspectFilter::processNineCellWindow | ( | float * | x11, |
float * | x21, | ||
float * | x31, | ||
float * | x12, | ||
float * | x22, | ||
float * | x32, | ||
float * | x13, | ||
float * | x23, | ||
float * | x33 | ||
) | [protected, virtual] |
Calculates output value from nine input values.
The input values and the output value can be equal to the \ nodata value if not present or outside of the border. Must be implemented by subclasses
Implements QgsDerivativeFilter.
Definition at line 31 of file qgsaspectfilter.cpp.
References QgsDerivativeFilter::calcFirstDerX(), QgsDerivativeFilter::calcFirstDerY(), M_PI, and QgsNineCellFilter::mOutputNodataValue.