Depression Filling
Raises cells in enclosed depressions to the minimum spill elevation needed to connect drainage downstream.
zfilled(p) ≥ z(p)
Best used when: spurious DEM pits would trap modelled flow.
DEM Fill Sinks
Remove artificial/internal depressions from a DEM to create a hydrologically connected surface for flow modelling.
HydrologyEnd-User DocumentationTheory + Formula + Parameters1. What This Feature Does
Remove artificial/internal depressions from a DEM to create a hydrologically connected surface for flow modelling.
Cloud workflow: choose data → configure the scientific method → run → review the resulting layer/report. No programming is required.
2. Recommended Workflow
Choose elevation band.
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Run sink filling.
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Compare the filled DEM with the original.
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Use the filled DEM for Flow Direction and Flow Accumulation when appropriate.
3. Theory, Methods & Equations
4. Input Data
| Input | Type | Requirement | Description |
|---|---|---|---|
| DEM Raster | raster | Required |
5. Parameters Available in the Application
| Parameter | Default | Choices / Range | How to Use It |
|---|---|---|---|
| Elevation Band | — | — |
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.
Important: Some real depressions are hydrologically meaningful. Filling every depression is a modelling assumption.
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.