eccodes/examples/python/grib_set_bitmap.py

# Copyright 2005-2016 ECMWF.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
#
# In applying this licence, ECMWF does not waive the privileges and immunities
# granted to it by virtue of its status as an intergovernmental organisation
# nor does it submit to any jurisdiction.

import traceback
import sys
from eccodes import *

INPUT = '../../data/regular_latlon_surface.grib1'
OUTPUT = 'out.bmp.grib'
MISSING = 9999
VERBOSE = 1  # verbose error reporting


def example():
    fin = open(INPUT)
    fout = open(OUTPUT, 'w')
    gid = codes_grib_new_from_file(fin)

    codes_set(gid, 'missingValue', MISSING)
    values = codes_get_values(gid)
    codes_set(gid, 'bitmapPresent', 1)
    # Change some data values to be missing
    num_missing = 0
    for i in range(100):
        if i % 2 == 0:
            values[i] = MISSING
            num_missing += 1
    codes_set_values(gid, values)

    # Check counts of missing and non-missing values
    num_data = codes_get(gid, 'numberOfDataPoints', int)
    assert(codes_get(gid, 'numberOfCodedValues', int)
           == num_data - num_missing)
    assert(codes_get(gid, 'numberOfMissing', int) == num_missing)

    codes_write(gid, fout)
    codes_release(gid)
    fin.close()
    fout.close()


def main():
    try:
        example()
    except CodesInternalError, err:
        if VERBOSE:
            traceback.print_exc(file=sys.stderr)
        else:
            print >> sys.stderr, err.msg

        return 1

if __name__ == "__main__":
    sys.exit(main())