Calculate Terrain Attributes
Overview
Calculates terrain attributes from an Input DEM raster file and outputs the corresponding terrain analysis result. The tool supports slope, aspect, curvature, and their variants.
Use Cases
- Basic preprocessing before terrain analysis such as slope orientation, solar radiation, and flow direction studies.
- Surface morphology studies such as landslide susceptibility, ecological suitability, and geomorphic zoning.
- Terrain factor input for hydrology analysis, soil erosion analysis, and engineering site selection.
Parameters
| Parameter | Description | Notes |
|---|---|---|
| Input DEM raster file | Input digital elevation model (DEM) raster file. | Required |
| Terrain attribute type | Terrain attribute type to calculate. | Required; default: slope_degrees; options: slope as rise/run (slope_riserun), slope as percent (slope_percentage), slope in degrees (slope_degrees), slope in radians (slope_radians), aspect (aspect), curvature (curvature), planform curvature (planform_curvature), profile curvature (profile_curvature) |
| Z-axis scale factor | Multiplier applied to elevation values before calculation. | Required; default: 1.0 |
| Output terrain attribute raster file | Output raster file containing the terrain attribute result. | Required |
Steps
- Start the tool: Open the Geoprocessing Toolbox, go to Thematic Analysis > Terrain Analysis, and start the Calculate Terrain Attributes tool.
- Prepare the input: Select the Input DEM raster file and confirm that the input data is complete and readable.
- Set core parameters: Configure Terrain attribute type and Z-axis scale factor according to the analysis objective.
- Set the output: Specify the Output terrain attribute raster file and confirm that the output path, format, and naming rules meet later workflow requirements.
- Run and inspect results: Click Run to execute the task. After it completes, check whether the result range, value distribution, and spatial location are as expected.
Notes
- When multiple rasters are used together, first confirm that their coordinate systems, resolutions, extents, and grid alignment are consistent.
- Voids, noise, and abnormal elevation values in the DEM directly affect terrain factors such as slope, aspect, and curvature.
- If the elevation unit differs from the horizontal unit, use the Z-axis scale factor to correct the vertical-to-horizontal ratio.