Base class for raster analysis methods that work with a 3x3 cell filter and calculate the value of each cell based on the cell value and the eight neighbour cells. More...

#include <qgsninecellfilter.h>

Inheritance diagram for QgsNineCellFilter:

[legend]

Public Types
enum class	Result : int { Success = 0 , InputLayerError = 1 , DriverError = 2 , CreateOutputError = 3 , InputBandError = 4 , OutputBandError = 5 , RasterSizeError = 6 , Canceled = 7 }
	Result of the calculation. More...

Public Member Functions
	QgsNineCellFilter (const QString &inputFile, const QString &outputFile, const QString &outputFormat)
	Constructor that takes input file, output file and output format (GDAL string)

virtual	~QgsNineCellFilter ()=default

double	cellSizeX () const

double	cellSizeY () const

QStringList	creationOptions () const
	Returns the list of data source creation options which will be used when creating the output raster file.

double	inputNodataValue () const

double	outputNodataValue () const

virtual float	processNineCellWindow (float x11, float x21, float x31, float x12, float x22, float x32, float x13, float x23, float *x33)=0
	Calculates output value from nine input values.

Result	processRaster (QgsFeedback *feedback=nullptr)
	Starts the calculation, reads from mInputFile and stores the result in mOutputFile.

void	setCellSizeX (double size)

void	setCellSizeY (double size)

void	setCreationOptions (const QStringList &list)
	Sets a list of data source creation options to use when creating the output raster file.

void	setInputNodataValue (double value)

void	setOutputNodataValue (double value)

void	setZFactor (double factor)

double	zFactor () const

Protected Attributes
double	mCellSizeX = -1.0

double	mCellSizeY = -1.0

QStringList	mCreationOptions

QString	mInputFile

double	mInputNodataValue = -1.0
	The nodata value of the input layer.

QString	mOutputFile

QString	mOutputFormat

double	mOutputNodataValue = -9999.0
	The nodata value of the output layer.

double	mZFactor = 1.0
	Scale factor for z-value if x-/y- units are different to z-units (111120 for degree->meters and 370400 for degree->feet)

Detailed Description

Base class for raster analysis methods that work with a 3x3 cell filter and calculate the value of each cell based on the cell value and the eight neighbour cells.

Common examples are slope and aspect calculation in DEMs. Subclasses only implement the method that calculates the new value from the nine values. Everything else (reading file, writing file) is done by this subclass

Definition at line 37 of file qgsninecellfilter.h.

Member Enumeration Documentation

◆ Result

enum class QgsNineCellFilter::Result : int

strong

Result of the calculation.

Since: QGIS 3.44

Enumerator
Success	Operation completed successfully.
InputLayerError	Error reading input file.
DriverError	Could not open the driver for the specified format.
CreateOutputError	Error creating output file.
InputBandError	Error reading input raster band.
OutputBandError	Error reading output raster band.
RasterSizeError	Raster height is too small (need at least 3 rows)
Canceled	User canceled calculation.

Definition at line 41 of file qgsninecellfilter.h.

Constructor & Destructor Documentation

◆ QgsNineCellFilter()

QgsNineCellFilter::QgsNineCellFilter	(	const QString &	inputFile,
		const QString &	outputFile,
		const QString &	outputFormat
	)

Constructor that takes input file, output file and output format (GDAL string)

Definition at line 36 of file qgsninecellfilter.cpp.

◆ ~QgsNineCellFilter()

virtual QgsNineCellFilter::~QgsNineCellFilter ( )

virtualdefault

Member Function Documentation

◆ cellSizeX()

double QgsNineCellFilter::cellSizeX ( ) const

inline

Definition at line 64 of file qgsninecellfilter.h.

◆ cellSizeY()

double QgsNineCellFilter::cellSizeY ( ) const

inline

Definition at line 66 of file qgsninecellfilter.h.

◆ creationOptions()

QStringList QgsNineCellFilter::creationOptions ( ) const

inline

Returns the list of data source creation options which will be used when creating the output raster file.

See also: setCreationOptions()

Since: QGIS 3.44

Definition at line 91 of file qgsninecellfilter.h.

◆ inputNodataValue()

double QgsNineCellFilter::inputNodataValue ( ) const

inline

Definition at line 72 of file qgsninecellfilter.h.

◆ outputNodataValue()

double QgsNineCellFilter::outputNodataValue ( ) const

inline

Definition at line 74 of file qgsninecellfilter.h.

◆ processNineCellWindow()

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

pure 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.

First index of the input cell is the row, second index is the column

Parameters

x11	surrounding cell top left
x21	surrounding cell central left
x31	surrounding cell bottom left
x12	surrounding cell top central
x22	the central cell for which the value will be calculated
x32	surrounding cell bottom central
x13	surrounding cell top right
x23	surrounding cell central right
x33	surrounding cell bottom right

Returns: the calculated cell value for the central cell x22

Implemented in QgsAspectFilter, QgsHillshadeFilter, QgsRuggednessFilter, QgsSlopeFilter, QgsTotalCurvatureFilter, and QgsDerivativeFilter.

◆ processRaster()

QgsNineCellFilter::Result QgsNineCellFilter::processRaster ( QgsFeedback * feedback = nullptr )

Starts the calculation, reads from mInputFile and stores the result in mOutputFile.

Parameters

feedback feedback object that receives update and that is checked for cancellation.

Returns: QgsNineCellFilter::Result::Success in case of success or error value on failure.

Definition at line 43 of file qgsninecellfilter.cpp.

◆ setCellSizeX()

void QgsNineCellFilter::setCellSizeX ( double size )

inline

Definition at line 65 of file qgsninecellfilter.h.

◆ setCellSizeY()

void QgsNineCellFilter::setCellSizeY ( double size )

inline

Definition at line 67 of file qgsninecellfilter.h.

◆ setCreationOptions()

void QgsNineCellFilter::setCreationOptions ( const QStringList & list )

inline

Sets a list of data source creation options to use when creating the output raster file.

See also: creationOptions()

Since: QGIS 3.44

Definition at line 83 of file qgsninecellfilter.h.

◆ setInputNodataValue()

void QgsNineCellFilter::setInputNodataValue ( double value )

inline

Definition at line 73 of file qgsninecellfilter.h.

◆ setOutputNodataValue()

void QgsNineCellFilter::setOutputNodataValue ( double value )

inline

Definition at line 75 of file qgsninecellfilter.h.

◆ setZFactor()

void QgsNineCellFilter::setZFactor ( double factor )

inline

Definition at line 70 of file qgsninecellfilter.h.

◆ zFactor()

double QgsNineCellFilter::zFactor ( ) const

inline

Definition at line 69 of file qgsninecellfilter.h.

Member Data Documentation

◆ mCellSizeX

double QgsNineCellFilter::mCellSizeX = -1.0

protected

Definition at line 172 of file qgsninecellfilter.h.

◆ mCellSizeY

double QgsNineCellFilter::mCellSizeY = -1.0

protected

Definition at line 173 of file qgsninecellfilter.h.

◆ mCreationOptions

QStringList QgsNineCellFilter::mCreationOptions

protected

Definition at line 170 of file qgsninecellfilter.h.

◆ mInputFile

QString QgsNineCellFilter::mInputFile

protected

Definition at line 167 of file qgsninecellfilter.h.

◆ mInputNodataValue

double QgsNineCellFilter::mInputNodataValue = -1.0

protected

The nodata value of the input layer.

Definition at line 175 of file qgsninecellfilter.h.

◆ mOutputFile

QString QgsNineCellFilter::mOutputFile

protected

Definition at line 168 of file qgsninecellfilter.h.

◆ mOutputFormat

QString QgsNineCellFilter::mOutputFormat

protected

Definition at line 169 of file qgsninecellfilter.h.

◆ mOutputNodataValue

double QgsNineCellFilter::mOutputNodataValue = -9999.0

protected

The nodata value of the output layer.

Definition at line 177 of file qgsninecellfilter.h.

◆ mZFactor

double QgsNineCellFilter::mZFactor = 1.0

protected

Scale factor for z-value if x-/y- units are different to z-units (111120 for degree->meters and 370400 for degree->feet)

Definition at line 179 of file qgsninecellfilter.h.

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

/build/qgis-3.43.0+git20250412+0bee5d6404c+99sid/src/analysis/raster/qgsninecellfilter.h
/build/qgis-3.43.0+git20250412+0bee5d6404c+99sid/src/analysis/raster/qgsninecellfilter.cpp

Public Types

Public Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ Result

Constructor & Destructor Documentation

◆ QgsNineCellFilter()

◆ ~QgsNineCellFilter()

Member Function Documentation

◆ cellSizeX()

◆ cellSizeY()

◆ creationOptions()

◆ inputNodataValue()

◆ outputNodataValue()

◆ processNineCellWindow()

◆ processRaster()

◆ setCellSizeX()

◆ setCellSizeY()

◆ setCreationOptions()

◆ setInputNodataValue()

◆ setOutputNodataValue()

◆ setZFactor()

◆ zFactor()

Member Data Documentation

◆ mCellSizeX

◆ mCellSizeY

◆ mCreationOptions

◆ mInputFile

◆ mInputNodataValue

◆ mOutputFile

◆ mOutputFormat

◆ mOutputNodataValue

◆ mZFactor