mirror of https://github.com/ecmwf/eccodes.git
92 lines
3.0 KiB
C
92 lines
3.0 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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* Description: How to use an iterator on lat/lon/values and query the bitmap
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* for missing values
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* (rather than compare each value with the missingValue key)
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "eccodes.h"
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static void usage(const char* prog)
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{
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printf("Usage: %s grib_file\n", prog);
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exit(1);
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}
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int main(int argc, char** argv)
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{
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FILE* in = NULL;
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int err = 0;
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double lat, lon, value;
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int n = 0;
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size_t bmp_len = 0, values_len = 0;
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char* filename = NULL;
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long bitmapPresent = 0;
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long* bitmap = NULL;
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double* values = NULL;
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codes_handle* h = NULL;
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codes_iterator* iter = NULL;
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if (argc != 2) usage(argv[0]);
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filename = argv[1];
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in = fopen(filename, "rb");
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if (!in) {
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fprintf(stderr, "ERROR: unable to open file %s\n", filename);
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return 1;
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}
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while ((h = codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err)) != NULL) {
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if (err != CODES_SUCCESS) CODES_CHECK(err, 0);
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CODES_CHECK(codes_get_long(h, "bitmapPresent", &bitmapPresent), 0);
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if (bitmapPresent) {
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CODES_CHECK(codes_get_size(h, "bitmap", &bmp_len), 0);
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bitmap = (long*)malloc(bmp_len * sizeof(long));
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CODES_CHECK(codes_get_long_array(h, "bitmap", bitmap, &bmp_len), 0);
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printf("Bitmap is present. Num = %zu\n", bmp_len);
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}
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/* sanity check. Number of values must match number in bitmap */
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CODES_CHECK(codes_get_size(h, "values", &values_len), 0);
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values = (double*)malloc(values_len * sizeof(double));
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CODES_CHECK(codes_get_double_array(h, "values", values, &values_len), 0);
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if (bitmapPresent) {
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assert(values_len == bmp_len);
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}
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/* a new iterator on lat/lon/values is created from the message handle h */
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iter = codes_grib_iterator_new(h, 0, &err);
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if (err != CODES_SUCCESS) CODES_CHECK(err, 0);
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n = 0;
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/* loop on all the lat/lon/values. Only print non-missing values */
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while (codes_grib_iterator_next(iter, &lat, &lon, &value)) {
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/* consult bitmap to see if the n'th value is missing */
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int is_missing_val = (bitmapPresent && bitmap[n] == 0);
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if (!is_missing_val) {
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printf("- %d - lat=%f lon=%f value=%f\n", n, lat, lon, value);
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}
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n++;
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}
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/* check number of elements in iterator matches value count */
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assert(n == values_len);
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codes_grib_iterator_delete(iter);
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codes_handle_delete(h);
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}
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fclose(in);
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return 0;
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}
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