Raster Terrain Modelling Plugin¶

The Raster Terrain Modelling plugin can be used to calculate the slope, aspect, ruggedness, and total curvature for digital elevation models (DEM). It is very simple to handle and provides an intuitive graphical user interface for creating new raster layers (See Figure plugins/plugins_raster_terrain/RasterTerrainDialog). The plugin requires the following parameters to be specified before running:

• Analysis: Can be one of slope, aspect, ruggedness, or total curvature.
• Input layer: Specify the input raster from a list of loaded raster layers.
• Output layer: Specify a name and path for the output raster file.
• Output format: Specify a format type for the output raster file. (Default is GeoTiff).

Description of the analysis:

• Slope: Calculates slope angle for each cell in degrees (based on first order derivative estimation).
• Aspect: Exposition (starting with 0 for north direction, in degrees counterclockwise).
• Ruggedness factor: A quantitative measurement of terrain heterogeneity.
• Total curvature: A curvature measure that combines plan- and profile curvature.

Raster Terrain Modelling Plugin

Using the plugin

1. Start QGIS and load a DEM raster layer.
2. Load the Raster Terrain Modelling plugin in the Plugin Manager see Section plugins/plugins/load_core_plugin and click on the Raster Terrain Modelling icon which appears in the QGIS toolbar menu. The Raster Terrain Modelling plugin dialog appears as shown in Figure plugins/plugins_raster_terrain/RasterTerrainDialog .
3. Select an analysis method (e.g. dropmenuopt{Slope}).
4. Specify an output file path, and an output file type.
5. Click Ok.