GIS raster utility methods

gis_utils.spread2d(obs[, msk, nodata, frc, ...])	Fill no-data cells with the nearest observation and return source and distance maps.
gis_utils.get_edge(a[, structure])	Get edge of valid cells.
gis_utils.reggrid_area(lats, lons)	Return cell areas [m2] for a regular geographic grid.