GIS

DEM Generation from SAR Data (Sentinel-1)

A site-specific digital elevation model built from Sentinel-1 radar imagery, where open global DEMs were too coarse and a ground survey was too slow.

Client: Infrastructure Planning TeamSurveying & InfrastructureJul 2020Project lead: M. A Zia

The challenge

The client needed terrain heights for a planning study and was stuck between two bad options. The freely available global elevation data was too coarse and too dated for the decisions they had to make, while commissioning a ground or LiDAR survey over that area would have taken longer and cost more than the study itself justified.

Our solution

We generated the elevation model from Sentinel-1 SAR using an interferometric workflow: selecting a suitable image pair, coregistration, interferogram formation, coherence assessment, phase filtering, unwrapping, conversion of unwrapped phase to height, and geocoding to the client's projection. The result was validated against reference elevation data and known control points before handover, and the areas of low coherence were reported honestly rather than smoothed over.

Results & impact

  • A site-specific DEM delivered in days, without a ground survey
  • Radar-derived elevation validated against reference data and control points
  • Low-confidence zones documented so planners knew what to trust
  • A repeatable SAR workflow the client can commission again for new sites

Technology

Sentinel-1 SARSNAPInSARSNAPHUArcGISQGIS

Skills applied

SAR InterferometryRadar Remote SensingTerrain & Elevation ModellingGeodesy & ProjectionsData ValidationGeography

Let's build something that delivers

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