FACT Elevation Computer
A REST API to compute land elevation statistics from satellite observations at a 30 meters scale. The data is from the Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) Version 3 (ASTGTM - https://lpdaac.usgs.gov/products/astgtmv003/), that provides a global digital elevation model (DEM) of land areas on Earth at a spatial resolution of 1 arc second (approximately 30 meter horizontal posting at the equator).
Use
The docker container can be started with the following code:
podman run -t -i --name fact_elevation -p 5003:5000 -d registry.git.nilu.no/fact/data/fact_elevation:0.3
The service could be queried passing the JSON polygon object as in:
curl -X POST http://localhost:5003/band_statistics \
-H "Content-Type: application/json" \
-d '{
"polygon_wkt": "POLYGON (())"
}'The polygon definition is made of several points coordinates, as in the case of polygon objects from shapefiles stored in databases. Polygon and COG rasters must share the same coordinate system, which in this case is lat and lon.
Specifications
The API is based on the Flask based web service provided by the FACT Utils polygonqueryonraster package from the the FACT Polygon Query on Raster project.
The data is from the Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) Version 3 (ASTGTM - https://lpdaac.usgs.gov/products/astgtmv003/), that provides a global digital elevation model (DEM) of land areas on Earth at a spatial resolution of 1 arc second (approximately 30 meter horizontal posting at the equator). Coverage is provided from from -83 to 83 degrees latitude.
Notes
Since this service is based on a continuous raster, results for polygon elevation will include:
- 'count' of pixels in the polygon,
- 'min' elevation,
- 'max' elevation,
- 'mean' elevation,
- 'std' standard deviation of elevation,
- 'median' elevation,
- 'entropy', which is the Shannon entropy measure of elevation data.
Authors
Riccardo Boero - ribo@nilu.no