mirror of https://github.com/ecmwf/eccodes.git
115 lines
3.5 KiB
C
115 lines
3.5 KiB
C
/*
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* (C) Copyright 2005- ECMWF.
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*
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* This software is licensed under the terms of the Apache Licence Version 2.0
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* which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
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*
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* In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
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* virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
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*/
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/*
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* C Implementation: get
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*
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* Description: how to get values using keys.
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*
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*
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "grib_api.h"
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int main(int argc, char** argv) {
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int err = 0;
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double *values = NULL;
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size_t values_len= 0;
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size_t i = 0;
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double latitudeOfFirstGridPointInDegrees;
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double longitudeOfFirstGridPointInDegrees;
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double latitudeOfLastGridPointInDegrees;
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double longitudeOfLastGridPointInDegrees;
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double jDirectionIncrementInDegrees;
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double iDirectionIncrementInDegrees;
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long numberOfPointsAlongAParallel;
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long numberOfPointsAlongAMeridian;
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double average = 0;
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FILE* in = NULL;
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char* filename = "../data/regular_latlon_surface.grib1";
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grib_handle *h = NULL;
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in = fopen(filename,"r");
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if(!in) {
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printf("ERROR: unable to open file %s\n",filename);
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return 1;
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}
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/* create new handle from a message in a file*/
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h = grib_handle_new_from_file(0,in,&err);
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if (h == NULL) {
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printf("Error: unable to create handle from file %s\n",filename);
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}
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/* get as a long*/
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GRIB_CHECK(grib_get_long(h,"numberOfPointsAlongAParallel",&numberOfPointsAlongAParallel),0);
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printf("numberOfPointsAlongAParallel=%ld\n",numberOfPointsAlongAParallel);
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/* get as a long*/
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GRIB_CHECK(grib_get_long(h,"numberOfPointsAlongAMeridian",&numberOfPointsAlongAMeridian),0);
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printf("numberOfPointsAlongAMeridian=%ld\n",numberOfPointsAlongAMeridian);
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/* get as a double*/
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GRIB_CHECK(grib_get_double(h,"latitudeOfFirstGridPointInDegrees",&latitudeOfFirstGridPointInDegrees),0);
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printf("latitudeOfFirstGridPointInDegrees=%g\n",latitudeOfFirstGridPointInDegrees);
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/* get as a double*/
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GRIB_CHECK(grib_get_double(h,"longitudeOfFirstGridPointInDegrees",&longitudeOfFirstGridPointInDegrees),0);
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printf("longitudeOfFirstGridPointInDegrees=%g\n",longitudeOfFirstGridPointInDegrees);
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/* get as a double*/
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GRIB_CHECK(grib_get_double(h,"latitudeOfLastGridPointInDegrees",&latitudeOfLastGridPointInDegrees),0);
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printf("latitudeOfLastGridPointInDegrees=%g\n",latitudeOfLastGridPointInDegrees);
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/* get as a double*/
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GRIB_CHECK(grib_get_double(h,"longitudeOfLastGridPointInDegrees",&longitudeOfLastGridPointInDegrees),0);
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printf("longitudeOfLastGridPointInDegrees=%g\n",longitudeOfLastGridPointInDegrees);
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/* get as a double*/
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GRIB_CHECK(grib_get_double(h,"jDirectionIncrementInDegrees",&jDirectionIncrementInDegrees),0);
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printf("jDirectionIncrementInDegrees=%g\n",jDirectionIncrementInDegrees);
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/* get as a double*/
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GRIB_CHECK(grib_get_double(h,"iDirectionIncrementInDegrees",&iDirectionIncrementInDegrees),0);
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printf("iDirectionIncrementInDegrees=%g\n",iDirectionIncrementInDegrees);
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/* get the size of the values array*/
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GRIB_CHECK(grib_get_size(h,"values",&values_len),0);
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values = malloc(values_len*sizeof(double));
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/* get data values*/
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GRIB_CHECK(grib_get_double_array(h,"values",values,&values_len),0);
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average = 0;
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for(i = 0; i < values_len; i++)
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average += values[i];
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average /=(double)values_len;
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free(values);
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printf("There are %d values, average is %g\n",(int)values_len,average);
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grib_handle_delete(h);
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fclose(in);
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return 0;
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}
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