mapping_var = 'mapping' for var in nc.variables.keys(): if hasattr(var, 'grid_mapping'): mapping_var = var.grid_mapping pass if not var in nc.variables.keys(): mapping = nc.createVariable(mapping_var, 'b') else: mapping = nc.variables[mapping_var] mapping.grid_mapping_name = "polar_stereographic" mapping.latitude_of_projection_origin = 90. mapping.straight_vertical_longitude_from_pole = -45.0 mapping.standard_parallel = 70.0 mapping.false_easting = 0. mapping.false_northing = 0. mapping.units = "m" # Save the projection information: nc.proj4 = "+init=epsg:3413" nc.Conventions = "CF-1.6" script_command = ' '.join([time.ctime(), ':', __file__.split('/')[-1]]) nc.history = script_command print "writing to %s ...\n" % output print "run nc2cdo.py to add lat/lon variables" nc.close()