DEM Filtering
Overview
This tool filters DEM cell values within a neighborhood window. It is suitable for smoothing noise, reducing artifacts, and preparing elevation data for terrain analysis. Different filtering methods can significantly affect terrain details and derived products.
Use Cases
- Smooth DEM noise before deriving slope, aspect, or curvature.
- Reduce artifacts in DEMs from urban, flat, hilly, or mountainous terrain.
- Prepare a standardized DEM input for longer iXGIS terrain or hydrology workflows.
Parameters
| Parameter | Description | Notes |
|---|---|---|
| Input DEM raster file | Digital Elevation Model (DEM) raster to filter. | Required. |
| Filtering method | DEM filtering method suitable for the terrain type. | Required. Default: traditional. Options: traditional method for flat terrain such as cities or plains (traditional), standard method for naturally undulating terrain such as hills or forests (standard), aggressive method for complex mountain areas such as cliffs or ridges (aggressive), hybrid terrain-stratified processing (hybrid). |
| Output filtered DEM file | Output DEM raster after filtering. | Required. |
Steps
- Open the Geoprocessing Toolbox in iXGIS, go to Spatial Analysis Tools > Neighborhood Analysis > Filters, and start DEM Filtering.
- Select the input DEM raster file and confirm that it can be read correctly.
- Select a filtering method based on the terrain type and analysis objective.
- Specify the output filtered DEM file and confirm the output path, format, and file name.
- Click Run. After the task completes, review the output elevation range, surface smoothness, and spatial alignment.
Notes
- Verify the DEM coordinate system, cell size, extent, and vertical units before filtering.
- Voids, noise, and abnormal elevation values in the DEM directly affect slope, aspect, curvature, and other terrain derivatives.