QgsKernelDensityEstimation Class Reference

Performs Kernel Density Estimation ("heatmap") calculations on a vector layer. More...

#include <qgskde.h>

Classes
struct	Parameters
	KDE parameters. More...

Public Types
enum	KernelShape {   KernelQuartic = 0, KernelTriangular, KernelUniform, KernelTriweight,   KernelEpanechnikov }
	Kernel shape type. More...
enum	OutputValues { OutputRaw = 0, OutputScaled }
	Output values type. More...
enum	Result {   Success, DriverError, InvalidParameters, FileCreationError,   RasterIoError }
	Result of operation. More...

Public Member Functions
	QgsKernelDensityEstimation (const Parameters &parameters, const QString &outputFile, const QString &outputFormat)
	Constructor for QgsKernelDensityEstimation. More...
	QgsKernelDensityEstimation (const QgsKernelDensityEstimation &other)=delete
	QgsKernelDensityEstimation cannot be copied. More...
Result	addFeature (const QgsFeature &feature)
	Adds a single feature to the KDE surface. More...
Result	finalise ()
	Finalises the output file. More...
QgsKernelDensityEstimation &	operator= (const QgsKernelDensityEstimation &other)=delete
	QgsKernelDensityEstimation cannot be copied. More...
Result	prepare ()
	Prepares the output file for writing and setups up the surface calculation. More...
Result	run ()
	Runs the KDE calculation across the whole layer at once. More...

Detailed Description

Performs Kernel Density Estimation ("heatmap") calculations on a vector layer.

Since

QGIS 3.0

Definition at line 39 of file qgskde.h.

Member Enumeration Documentation

enum QgsKernelDensityEstimation::KernelShape

Kernel shape type.

Enumerator
KernelQuartic	Quartic kernel.
KernelTriangular	Triangular kernel.
KernelUniform	Uniform (flat) kernel.
KernelTriweight	Triweight kernel.
KernelEpanechnikov	Epanechnikov kernel.

Definition at line 44 of file qgskde.h.

enum QgsKernelDensityEstimation::OutputValues

Output values type.

Enumerator
OutputRaw	Output the raw KDE values.
OutputScaled	Output mathematically correct scaled values.

Definition at line 54 of file qgskde.h.

enum QgsKernelDensityEstimation::Result

Result of operation.

Enumerator
Success	Operation completed successfully.
DriverError	Could not open the driver for the specified format.
InvalidParameters	Input parameters were not valid.
FileCreationError	Error creating output file.
RasterIoError	Error writing to raster.

Definition at line 61 of file qgskde.h.

Constructor & Destructor Documentation

QgsKernelDensityEstimation::QgsKernelDensityEstimation	(	const Parameters &	parameters,
		const QString &	outputFile,
		const QString &	outputFormat
	)

Constructor for QgsKernelDensityEstimation.

Requires a Parameters object specifying the options to use to generate the surface. The output path and file format are also required.

Definition at line 23 of file qgskde.cpp.

QgsKernelDensityEstimation::QgsKernelDensityEstimation ( const QgsKernelDensityEstimation &  other )

delete

QgsKernelDensityEstimation cannot be copied.

Member Function Documentation

QgsKernelDensityEstimation::Result QgsKernelDensityEstimation::addFeature

(

const QgsFeature &

feature

)

Adds a single feature to the KDE surface.

prepare() must be called before adding features.

See also

prepare()

finalise()

Definition at line 107 of file qgskde.cpp.

QgsKernelDensityEstimation::Result QgsKernelDensityEstimation::finalise

(

)

Finalises the output file.

Must be called after adding all features via addFeature().

See also

prepare()

addFeature()

Definition at line 208 of file qgskde.cpp.

QgsKernelDensityEstimation& QgsKernelDensityEstimation::operator= ( const QgsKernelDensityEstimation &  other )

delete

QgsKernelDensityEstimation cannot be copied.

QgsKernelDensityEstimation::Result QgsKernelDensityEstimation::prepare

(

)

Prepares the output file for writing and setups up the surface calculation.

This must be called before adding features via addFeature().

See also

addFeature()

finalise()

Definition at line 69 of file qgskde.cpp.

QgsKernelDensityEstimation::Result QgsKernelDensityEstimation::run

(

)

Runs the KDE calculation across the whole layer at once.

Either call this method, or manually call run(), addFeature() and finalise() separately.

Definition at line 44 of file qgskde.cpp.

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

• /build/qgis-3.4.15+24xenial/src/analysis/raster/qgskde.h
• /build/qgis-3.4.15+24xenial/src/analysis/raster/qgskde.cpp