Raster Caster

A QGIS plugin that casts elevation values onto a raster using surface polygons and elevation points stored in a GeoPackage.

Usage

The plugin adds a Raster Caster provider to the Processing Toolbox with two algorithms.

1. Begin new

Creates an empty GeoPackage in the CRS of your choice (EPSG:28992 by default) and loads its two layers into the project:

• surface (Polygon): the areas to cast.
  • definition_type = 'constant': param_1 holds the elevation value.
  • definition_type = 'tin': the elevation is interpolated from the elevation points inside the surface.
• elevation point (Point): supporting points for TIN surfaces. The elevation attribute is used to define height. Set in_polygon_only to true to restrict a point to the surfaces it actually lies inside.

2. Cast

Burns the surfaces into a new raster. Constant surfaces are rasterized with their param_1 value; TIN surfaces are interpolated from the elevation points they contain.

• Surface layer: polygons with the definition_type and param_1 fields, as created by Begin new.
• Elevation point layer: points with an elevation and in_polygon_only field.
• Input Raster: optional; its extent and pixel size are used for the output. Surfaces are cast onto this raster.
• Pixel Size: output resolution, required when no input raster is given.
• Snapping distance: search buffer around a TIN surface for elevation points that lie just outside it. Points with in_polygon_only set are not picked up by this buffer.

Without an input raster, the output extent follows the extent of the surface layer.

Development

Run the tests in the provided container:

docker compose build
docker compose run --rm qgis pytest

Build an installable plugin zip:

python zip_plugin.py