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Description

This example shows:

...

how to create a multi field message in memory and write it in a file. The multi field messages can be created only in GRIB edition 2.

Source code

Tabs Container
directionhorizontal


Tabs Page
titleCFortran 90


Code Block
languagecppnone
titlegrib_multi_write.cf90
linenumbersfalse
/*
 *! (C) Copyright 2005-2015 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 ImplementationDescription: grib_multi_write
 *
 * Description: How to encode GRIB2 messages containing multiple fields
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "eccodes.h"

void usage(const char* prog) {
    printf("usage: %s in.grib out.grib\n",prog);
    exit(1);
}

int main(int argc, char** argv)
{
    int err = 0;
    FILE* in = NULL;
    FILE* of = NULL;
    long edition, step;
    char* filename=NULL;
    char* ofilename=NULL;
    codes_handle *h = NULL;
    codes_multi_handle *mh=NULL;
    const int start_section = 4; /* Grib2 Product Definition Section */

    if (argc < 3) usage(argv[0]);
    filename=argv[1];
    ofilename=argv[2];

    /* open input file */
    in = fopen(filename,"r");
    if(!in) {
how to create a multi field message in memory and write
!               it in a file. The multi field messages can be created
!               only in GRIB edition 2.
!
!
!
program grib2_multi_write
  use eccodes
  implicit none
  integer                            :: infile,outfile
  integer                            :: in_gribid
  integer                           fprintf(stderr, "ERROR: unable to open input file %s\n",filename);
 :: multi_gribid
  integer             return 1;
    }

    /* new grib handle from input file */:: step,startsection

  ! multi field messages hcan be = codes_handle_new_from_file(0,created only in, PRODUCT_GRIB, &err);edition 2
  call  CODES_CHECK(err,0);codes_open_file(infile,'../../data/sample.grib2','r')

   call CODES_CHECK(codes_getopen_longfile(h,"edition",&edition),0);outfile,'multi_created.grib2','w')

  !  if (edition != 2) {   a grib message is loaded from file
  !      fprintf(stderr, "ERROR: Input grib must be edition 2 for multi fields\n");
        exit(1);
    }

    /* create a new empty multi field handle */
    mh=codes_grib_multi_handle_new(0);
    if (!mh) {
        fprintf(stderr,"ERROR: Unable to create multi field handle\n");
        exit(1);
    }

    for (step=12;step<=120;step+=12) {
        /* set step */
        codes_set_long(h,"step",step);
        /* append h to mh repeating from section 4 */
        /* i.e. starting from section 4 all the sections to the end of the message will be copied */in_gribid is the grib id to be used in subsequent calls
  call codes_grib_new_from_file(infile,in_gribid)

  startsection=4
  do step=0,240,12

    call codes_set(in_gribid,"step",step)
    call codes_grib_multi_append(in_gribid,startsection,multi_gribid)

  enddo

!  write messages to a file
  call codes_grib_multi_write(multi_gribid,outfile)

  call codes_release(in_gribid)
  call codes_release(multi_gribid)

  call codes_close_file(infile)
  call codes_close_file(outfile)

end program grib2_multi_write



Tabs Page
titlePython


Code Block
languagepython
titlegrib_multi_write.py
linenumbersfalse
#
# (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.
#

import traceback
import sys

from eccodes import *

INPUT = '../../data/sample.grib2'
OUTPUT = 'out.mw.grib'
VERBOSE = 1  # verbose error reporting


def example():
    fin = open(INPUT, 'rb')
    fout = open(OUTPUT, 'wb')

    gid = codes_grib_new_from_file(fin)

    mgid = codes_grib_multi_new()

    for step in range(12, 132, 12):
        codes_set(gid, "step", step)
        codes_grib_multi_handle_append(hgid, start_section4, mhmgid);

    } codes_grib_multi_write(mgid, fout)

    /* open output file */codes_grib_multi_release(mgid)
    codes_release(gid)
    of=fopen(ofilename,"w");fin.close()
    if(!of) { fout.close()


def main():
    try:
        fprintf(stderr, "ERROR: unable to open output file %s\n",ofilename);
example()
    except CodesInternalError as err:
        if VERBOSE:
         exit(1);   traceback.print_exc(file=sys.stderr)
    }

    /*else:
 write multi fields handle to output file */
    codes_grib_multi_handle_write(mh,of);
    fclose(of);

    /* release memory */
    codes_handle_delete(h);
    codes_grib_multi_handle_delete(mh);

    fclose(in);
    return 0;
}
Tabs Page
titleFortran 90
sys.stderr.write(err.msg + '\n')

        return 1


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



Tabs Page
titleC


Code Block
languagecpp
Code Block
languagenone
titlegrib_multi_write.f90c
linenumbersfalse
!/*
 * (C) Copyright 2005-2015 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: grib_multi_write
 *
 * Description: howHow to createencode aGRIB2 multimessages fieldcontaining messagemultiple infields
 memory and write
!        *
 */
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "eccodes.h"

static void usage(const char* prog) {
       itprintf("usage: %s in.grib a file. The multi field messages can be created
!    out.grib\n",prog);
    exit(1);
}

int main(int argc, char** argv)
{
    int err = 0;
    onlyFILE* in GRIB edition 2.
!
!
!
program grib2_multi_write
  use eccodes
  implicit none
  integer    = NULL;
    FILE* of = NULL;
    long edition, step;
    char* filename=NULL;
    char* ofilename=NULL;
    codes_handle *h = NULL;
       :: infile,outfilecodes_multi_handle *mh=NULL;
  integer  const int start_section = 4; /* Grib2 Product Definition Section */

    if (argc < 3) usage(argv[0]);
    filename=argv[1];
    :: in_gribid,iretofilename=argv[2];

  integer  /* open input file */
    in = fopen(filename,"r");
    if(!in) {
           :: multi_gribid
  integer   fprintf(stderr, "ERROR: unable to open input file %s\n",filename);
        return 1;
    }

    /* new grib handle from input   :: step,startsection
file */
  ! multi fieldh messages can be created only in edition 2 
  call codes_open_file(infile,'../../data/sample.grib2','r')

  call codes_open_file(outfile,'multi_created.grib2','w')

  !     a grib message is loaded from file
  !     in_gribid is the grib id to be used in subsequent calls
  call codes_grib_new_from_file(infile,in_gribid)

  startsection=4
  do step=0,240,12

    call codes_set(in_gribid,"step",step)
    call codes_grib_multi_append(in_gribid,startsection,multi_gribid)

  enddo

!  write messages to a file
  call codes_grib_multi_write(multi_gribid,outfile)

  call codes_release(in_gribid)
  call codes_release(multi_gribid)

  call codes_close_file(infile)
  call codes_close_file(outfile)

end program grib2_multi_write
Tabs Page
titlePython
Code Block
languagepython
titlegrib_multi_write.py
linenumbersfalse
#
# Copyright 2005-2015 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/sample.grib2'
OUTPUT='out.mw.grib'
VERBOSE=1 # verbose error reporting

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

    gid = codes_grib_new_from_file(fin)

    mgid = codes_grib_multi_new()

    for step in range(12,132,12):
        codes_set(gid,"step",step)= codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err);
    CODES_CHECK(err,0);
    CODES_CHECK(codes_get_long(h,"edition",&edition),0);
    if (edition != 2) {
        fprintf(stderr, "ERROR: Input grib must be edition 2 for multi fields\n");
        exit(1);
    }

    /* create a new empty multi field handle */
    mh=codes_grib_multi_handle_new(0);
    if (!mh) {
        fprintf(stderr,"ERROR: Unable to create multi field handle\n");
        exit(1);
    }

    for (step=12;step<=120;step+=12) {
        /* set step */
        codes_set_long(h,"step",step);
        /* append h to mh repeating from section 4 */
        /* i.e. starting from section 4 all the sections to the end of the message will be copied */
        codes_grib_multi_handle_append(gid,4,mgid)

h, start_section, mh);
    codes_grib_multi_write(mgid,fout)}

    codes_grib_multi_release(mgid)
    codes_release(gid)/* open output file */
    fin.close()of=fopen(ofilename,"w");
    fout.closeif(!of) 

def main():
    try:{
        examplefprintf()
    except CodesInternalError,err:
        if VERBOSE:stderr, "ERROR: unable to open output file %s\n",ofilename);
        exit(1);
    traceback.print_exc(file=sys.stderr)}

    /* write multi fields else:
handle to output file */
    codes_grib_multi_handle_write(mh,of);
    print >>sys.stderr,err.msgfclose(of);

    /* release memory */
 return  1

if codes__name__ == "__main__":handle_delete(h);
    codes_grib_multi_handle_delete(mh);

    sys.exit(main())fclose(in);
    return 0;
}