Class: QgsKernelDensityEstimation

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

Enums

KernelShape	Kernel shape type
OutputValues	Output values type
Result	Result of operation

Methods

addFeature	Adds a single feature to the KDE surface.
finalise	Finalises the output file.
prepare	Prepares the output file for writing and setups up the surface calculation.
run	Runs the KDE calculation across the whole layer at once.

class qgis.analysis.QgsKernelDensityEstimation

Bases: object

__init__(parameters: QgsKernelDensityEstimation.Parameters, outputFile: str | None, outputFormat: str | None)

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.

Parameters:

• parameters (QgsKernelDensityEstimation.Parameters)

• outputFile (Optional[str])

• outputFormat (Optional[str])

class KernelShape(*values)

Bases: IntEnum

Kernel shape type

• Quartic: Quartic kernel

  Available as QgsKernelDensityEstimation.KernelQuartic in older QGIS releases.

• Triangular: Triangular kernel

  Available as QgsKernelDensityEstimation.KernelTriangular in older QGIS releases.

• Uniform: Uniform (flat) kernel

  Available as QgsKernelDensityEstimation.KernelUniform in older QGIS releases.

• Triweight: Triweight kernel

  Available as QgsKernelDensityEstimation.KernelTriweight in older QGIS releases.

• Epanechnikov: Epanechnikov kernel

  Available as QgsKernelDensityEstimation.KernelEpanechnikov in older QGIS releases.

class OutputValues(*values)

Bases: IntEnum

Output values type

• Raw: Output the raw KDE values

  Available as QgsKernelDensityEstimation.OutputRaw in older QGIS releases.

• Scaled: Output mathematically correct scaled values

  Available as QgsKernelDensityEstimation.OutputScaled in older QGIS releases.

class Parameters

Bases: object

KDE parameters

decayRatio: float

Decay ratio (Triangular kernels only)

outputValues: QgsKernelDensityEstimation.OutputValues

Type of output value

pixelSize: float

Size of pixel in output file

radius: float

Fixed radius, in map units

radiusField: str

Field for radius, or empty if using a fixed radius

shape: QgsKernelDensityEstimation.KernelShape

Kernel shape

source: QgsFeatureSource

Point feature source

weightField: str

Field name for weighting field, or empty if not using weights

class Result(*values)

Bases: IntEnum

Result of operation

• 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

addFeature(self, feature: QgsFeature) → QgsKernelDensityEstimation.Result

Adds a single feature to the KDE surface. prepare() must be called before adding features.

See also

prepare()

See also

finalise()

Parameters:

feature (QgsFeature)

Return type:

QgsKernelDensityEstimation.Result

finalise(self) → QgsKernelDensityEstimation.Result

Finalises the output file. Must be called after adding all features via addFeature().

See also

prepare()

See also

addFeature()

Return type:

QgsKernelDensityEstimation.Result

prepare(self) → QgsKernelDensityEstimation.Result

Prepares the output file for writing and setups up the surface calculation. This must be called before adding features via addFeature().

See also

addFeature()

See also

finalise()

Return type:

QgsKernelDensityEstimation.Result

run(self) → QgsKernelDensityEstimation.Result

Runs the KDE calculation across the whole layer at once. Either call this method, or manually call run(), addFeature() and finalise() separately.

Return type:

QgsKernelDensityEstimation.Result