oggm.tasks.define_glacier_region(gdir, entity=None, source=None)[source]

Very first task after initialization: define the glacier’s local grid.

Defines the local projection (Transverse Mercator), centered on the glacier. There is some options to set the resolution of the local grid. It can be adapted depending on the size of the glacier with:

dx (m) = d1 * AREA (km) + d2 ; clipped to dmax


or be set to a fixed value. See params.cfg for setting these options. Default values of the adapted mode lead to a resolution of 50 m for Hintereisferner, which is approx. 8 km2 large. After defining the grid, the topography and the outlines of the glacier are transformed into the local projection. The default interpolation for the topography is cubic.

Parameters: gdir : oggm.GlacierDirectory where to write the data entity : geopandas.GeoSeries the glacier geometry to process - DEPRECATED. It is now ignored source : str or list of str, optional If you want to force the use of a certain DEM source. Available are: ‘USER’ : file set in cfg.PATHS[‘dem_file’] ‘SRTM’ : http://srtm.csi.cgiar.org/ ‘GIMP’ : https://bpcrc.osu.edu/gdg/data/gimpdem ‘RAMP’ : http://nsidc.org/data/docs/daac/nsidc0082_ramp_dem.gd.html ‘REMA’ : https://www.pgc.umn.edu/data/rema/ ‘DEM3’ : http://viewfinderpanoramas.org/ ‘ASTER’ : https://lpdaac.usgs.gov/products/astgtmv003/ ‘TANDEM’ : https://geoservice.dlr.de/web/dataguide/tdm90/ ‘ARCTICDEM’ : https://www.pgc.umn.edu/data/arcticdem/ ‘AW3D30’ : https://www.eorc.jaxa.jp/ALOS/en/aw3d30 ‘MAPZEN’ : https://registry.opendata.aws/terrain-tiles/ ‘ALASKA’ : https://www.the-cryosphere.net/8/503/2014/ ‘COPDEM’ : Copernicus DEM GLO-90 https://bit.ly/2T98qqs ‘NASADEM’: https://lpdaac.usgs.gov/products/nasadem_hgtv001/

Notes

Files writen to the glacier directory:
dem.tif
A geotiff file containing the DEM (reprojected into the local grid).This DEM is not smoothed or gap files, and is the closest to the original DEM source.
glacier_grid.json
A salem.Grid handling the georeferencing of the local grid.
outlines.shp
The glacier outlines in the local map projection (Transverse Mercator).