DEM Aspect

Calculate the compass direction of maximum downslope gradient from a DEM.

Terrain / ElevationEnd-User DocumentationTheory + Formula + Parameters

1. What This Feature Does

Calculate the compass direction of maximum downslope gradient from a DEM.

Cloud workflow: choose data → configure the scientific method → run → review the resulting layer/report. No programming is required.

2. Recommended Workflow

Choose elevation band. ↓ Set the value used for flat areas. ↓ Run aspect. ↓ Interpret aspect only where slope is meaningful.

3. Theory, Methods & Equations

Aspect from Elevation Gradient

Uses X/Y terrain derivatives to calculate downhill orientation.

Aspect = atan2(∂z/∂y, −∂z/∂x) converted to 0–360°
Best used when: slope orientation affects solar radiation, vegetation, moisture, visibility or terrain processes.

4. Input Data

InputTypeRequirementDescription
DEM RasterrasterRequired

5. Parameters Available in the Application

ParameterDefaultChoices / RangeHow to Use It
Elevation Band——
Flat Area Value-1—

6. Output & Interpretation

The result should be interpreted according to the selected method and the physical meaning of the input data. Preserve source units, coordinate reference information, NoData meaning, acquisition date, and preprocessing level when comparing results.

Scientific interpretation: an algorithm can produce a numerically valid result even when the input data are unsuitable. Always check masks, units, sensor characteristics, spatial resolution and reference data.

7. Best Practices

  • Use analysis-ready inputs and remove invalid/cloud/noise artifacts that are not part of the target phenomenon.
  • Choose parameters from the physical scale of the data, not only from visual appearance.
  • Keep categorical and continuous rasters conceptually separate when selecting interpolation/resampling methods.
  • Compare the result with the source image and independent reference information.
  • Document the settings used when results will be compared across dates, sensors or study areas.
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