QGIS API Documentation  2.18.21-Las Palmas (9fba24a)
Public Member Functions | Protected Member Functions | List of all members
QgsDerivativeFilter Class Referenceabstract

Adds the ability to calculate derivatives in x- and y-directions. More...

#include <qgsderivativefilter.h>

Inheritance diagram for QgsDerivativeFilter:
Inheritance graph
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Public Member Functions

 QgsDerivativeFilter (const QString &inputFile, const QString &outputFile, const QString &outputFormat)
 
virtual ~QgsDerivativeFilter ()
 
virtual float processNineCellWindow (float *x11, float *x21, float *x31, float *x12, float *x22, float *x32, float *x13, float *x23, float *x33) override=0
 Calculates output value from nine input values. More...
 
- Public Member Functions inherited from QgsNineCellFilter
 QgsNineCellFilter (const QString &inputFile, const QString &outputFile, const QString &outputFormat)
 Constructor that takes input file, output file and output format (GDAL string) More...
 
virtual ~QgsNineCellFilter ()
 
double cellSizeX () const
 
double cellSizeY () const
 
double inputNodataValue () const
 
double outputNodataValue () const
 
int processRaster (QProgressDialog *p)
 Starts the calculation, reads from mInputFile and stores the result in mOutputFile. More...
 
void setCellSizeX (double size)
 
void setCellSizeY (double size)
 
void setInputNodataValue (double value)
 
void setOutputNodataValue (double value)
 
void setZFactor (double factor)
 
double zFactor () const
 

Protected Member Functions

float calcFirstDerX (float *x11, float *x21, float *x31, float *x12, float *x22, float *x32, float *x13, float *x23, float *x33)
 Calculates the first order derivative in x-direction according to Horn (1981) More...
 
float calcFirstDerY (float *x11, float *x21, float *x31, float *x12, float *x22, float *x32, float *x13, float *x23, float *x33)
 Calculates the first order derivative in y-direction according to Horn (1981) More...
 

Additional Inherited Members

- Protected Attributes inherited from QgsNineCellFilter
double mCellSizeX
 
double mCellSizeY
 
QString mInputFile
 
float mInputNodataValue
 The nodata value of the input layer. More...
 
QString mOutputFile
 
QString mOutputFormat
 
float mOutputNodataValue
 The nodata value of the output layer. More...
 
double mZFactor
 Scale factor for z-value if x-/y- units are different to z-units (111120 for degree->meters and 370400 for degree->feet) More...
 

Detailed Description

Adds the ability to calculate derivatives in x- and y-directions.

Needs to be subclassed (e.g. for slope and aspect)

Definition at line 25 of file qgsderivativefilter.h.

Constructor & Destructor Documentation

◆ QgsDerivativeFilter()

QgsDerivativeFilter::QgsDerivativeFilter ( const QString inputFile,
const QString outputFile,
const QString outputFormat 
)

Definition at line 20 of file qgsderivativefilter.cpp.

◆ ~QgsDerivativeFilter()

QgsDerivativeFilter::~QgsDerivativeFilter ( )
virtual

Definition at line 26 of file qgsderivativefilter.cpp.

Member Function Documentation

◆ calcFirstDerX()

float QgsDerivativeFilter::calcFirstDerX ( float *  x11,
float *  x21,
float *  x31,
float *  x12,
float *  x22,
float *  x32,
float *  x13,
float *  x23,
float *  x33 
)
protected

Calculates the first order derivative in x-direction according to Horn (1981)

Definition at line 31 of file qgsderivativefilter.cpp.

◆ calcFirstDerY()

float QgsDerivativeFilter::calcFirstDerY ( float *  x11,
float *  x21,
float *  x31,
float *  x12,
float *  x22,
float *  x32,
float *  x13,
float *  x23,
float *  x33 
)
protected

Calculates the first order derivative in y-direction according to Horn (1981)

Definition at line 98 of file qgsderivativefilter.cpp.

◆ processNineCellWindow()

virtual float QgsDerivativeFilter::processNineCellWindow ( float *  x11,
float *  x21,
float *  x31,
float *  x12,
float *  x22,
float *  x32,
float *  x13,
float *  x23,
float *  x33 
)
overridepure 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 QgsNineCellFilter.

Implemented in QgsHillshadeFilter, QgsAspectFilter, and QgsSlopeFilter.


The documentation for this class was generated from the following files: