Description

This example shows: how to read all the expanded data values from BUFR messages.

Source code

bufr_expanded.f90
!
! (C) Copyright 2005- 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.
!
!
! FORTRAN 90 Implementation: bufr_expanded
!
! Description: how to read all the expanded data values from BUFR messages.
!
!
program bufr_expanded
use eccodes
implicit none
integer            :: ifile
integer            :: iret
integer            :: ibufr
integer            :: i
integer            :: count=0
integer(kind=4)    :: numberOfValues
real(kind=8), dimension(:), allocatable       :: values

  call codes_open_file(ifile,'../../data/bufr/syno_1.bufr','r')

  ! The first bufr message is loaded from file,
  ! ibufr is the bufr id to be used in subsequent calls
  call codes_bufr_new_from_file(ifile,ibufr,iret)

  do while (iret/=CODES_END_OF_FILE)

    write(*,*) 'message: ',count

    ! We need to instruct ecCodes to expand all the descriptors
    ! i.e. unpack the data values
    call codes_set(ibufr,"unpack",1);

    ! Get the expanded data values
    call codes_get(ibufr,'numericValues',values)

    numberOfValues=size(values)

    do i=1,numberOfValues
        write(*,*) '  ',i,values(i)
    enddo

    ! Release the bufr message
    call codes_release(ibufr)

    ! Load the next bufr message
    call codes_bufr_new_from_file(ifile,ibufr,iret)

    ! Free array
    deallocate(values)

    count=count+1

  end do

  ! Close file
  call codes_close_file(ifile)

end program bufr_expanded
bufr_expanded.py
# Copyright 2005- 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.

#
# Python implementation: bufr_get_keys
#
# Description: how to read values of different type of keys from BUFR messages.
#
#

from __future__ import absolute_import

import sys
import traceback

from eccodes import *

INPUT = '../../data/bufr/syno_1.bufr'
VERBOSE = 1  # verbose error reporting


def example():
    # open bufr file
    f = open(INPUT, 'rb')

    cnt = 0

    # loop for the messages in the file
    while 1:
        # get handle for message
        bufr = codes_bufr_new_from_file(f)
        if bufr is None:
            break

        print("message: %s" % cnt)

        # we need to instruct ecCodes to expand all the descriptors
        # i.e. unpack the data values
        codes_set(bufr, 'unpack', 1)

        # ----------------------------------
        # get all the expanded data values
        # ----------------------------------
        key = 'numericValues'

        # get size
        num = codes_get_size(bufr, key)
        print('  size of %s is: %s' % (key, num))

        # get values
        values = codes_get_array(bufr, key)
        for i in range(len(values)):
            print("   %d %.10e" % (i + 1, values[i]))

        cnt += 1

        # delete handle
        codes_release(bufr)

    # close the file
    f.close()


def main():
    try:
        example()
    except CodesInternalError as err:
        if VERBOSE:
            traceback.print_exc(file=sys.stderr)
        else:
            sys.stderr.write(err.msg + '\n')

        return 1


if __name__ == "__main__":
    sys.exit(main())
bufr_expanded.c
/*
 * Copyright 2005- 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.
 */

/*
 * C Implementation: bufr_expanded
 *
 * Description: how to read all the expanded data values from BUFR messages.
 *
 */

#include "eccodes.h"

static void usage(const char* prog) {
    printf("usage: %s infile\n",prog);
    exit(1);
}

int main(int argc,char* argv[])
{
    char* filename = NULL;
    FILE* in = NULL;

    /* message handle. Required in all the ecCodes calls acting on a message.*/
    codes_handle* h=NULL;

    double *values = NULL;
    size_t values_len=0;
    int i, err=0;
    int cnt=0;

    if (argc!=2) usage(argv[0]);

    filename=argv[1];

    /* open bufr file */
    in=fopen(filename,"rb");
    if (!in) {
        printf("ERROR: unable to open file %s\n", filename);
        return 1;
    }

    /* loop over the messages in the bufr file */
    while ((h = codes_handle_new_from_file(NULL, in, PRODUCT_BUFR, &err)) != NULL || err != CODES_SUCCESS)
    {
        if (h == NULL) {
            printf("Error: unable to create handle for message %d\n",cnt);
            cnt++;
            continue;
        }

        /* get the size of the values array*/
        CODES_CHECK(codes_get_size(h, "numericValues", &values_len),0);
        printf("  number of expanded values: %lu\n", values_len);

        /* allocate array for data values */
        values = (double*)malloc(values_len*sizeof(double));

        /* get the expanded data values*/
        CODES_CHECK(codes_get_double_array(h, "numericValues", values, &values_len),0);

        for(i = 0; i < values_len; i++)
        {
            printf("  %.10e\n",values[i]);
        }

        free(values);

        /* delete handle */
        codes_handle_delete(h);

        cnt++;
    }

    fclose(in);
    return 0;
}