Class: QgsElevationMap

class qgis.core.QgsElevationMap

Bases: sip.wrapper

Stores digital elevation model in a raster image which may get updated as a part of map layer rendering process. Afterwards the elevations can be used for post-processing effects of the rendered color map image.

Elevations are encoded as colors in QImage, thanks to this it is not only possible to set elevation for each pixel, but also to use QPainter for more complex updates of elevations. We encode elevations to 24 bits in range of [-8000, 8777] with precision of three decimal digits, which should give millimiter precision and enough range for elevation values in meters.

New in version 3.28.

QgsElevationMap(size: QSize) Constructs an elevation map with the given width and height

Methods

applyEyeDomeLighting

Applies eye dome lighting effect to the given image.

decodeElevation

Converts a color back to elevation value

encodeElevation

Converts elevation value to an actual color

painter

Returns painter to the underlying QImage with elevations

rawElevationImage

Returns raw elevation image with elevations encoded as color values

applyEyeDomeLighting(self, img: QImage, distance: int, strength: float, rendererScale: float)

Applies eye dome lighting effect to the given image. The effect makes angled surfaces darker and adds silhouettes in case of larger differences of elevations between neighboring pixels.

The distance parameter tells how many pixels away from the original pixel to sample neighboring pixels. Normally distance of 2 pixels gives good results.

The strength parameter adjusts how strong the added shading will be. Good default for this value seems to be 1000.

The zScale parameter adjusts scale of elevation values. It is recommended to set this to the map’s scale denominator to get similarly looking results at different map scales.

Parameters
  • img (QImage) –

  • distance (int) –

  • strength (float) –

  • rendererScale (float) –

decodeElevation(colorRaw: int) float

Converts a color back to elevation value

Parameters

colorRaw (int) –

Return type

float

encodeElevation(z: float) int

Converts elevation value to an actual color

Parameters

z (float) –

Return type

int

painter(self) QPainter

Returns painter to the underlying QImage with elevations

Return type

QPainter

rawElevationImage(self) QImage

Returns raw elevation image with elevations encoded as color values

Return type

QImage