1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include "grib_api.h"
int main(int argc, char *argv[])
{
int ret=0;
FILE* f;
size_t size;
grib_handle* h=NULL;
double* values=NULL;
long numberOfPointsAlongAParallel,numberOfPointsAlongAMeridian,numberOfPoints,i,j,k;
char* filename="out.grib";
const void* buffer=NULL;
/* Create a grib handle from template*/
h = grib_handle_new_from_template(0,"GRIB1");
if(!h) {
printf("ERROR: Unable to create grib handle\n");
exit(1);
}
/* set values as appropriate in the grib handle header */
CHECK(grib_set_long(h,"gribTablesVersionNo", 210));
CHECK(grib_set_long(h,"indicatorOfParameter",80 ));
CHECK(grib_set_long(h,"indicatorOfTypeOfLevel",1 ));
CHECK(grib_set_long(h,"topLevel",0));
CHECK(grib_set_long(h,"bottomLevel",0));
CHECK(grib_set_long(h,"dataDate",20021201 ));
CHECK(grib_set_long(h,"dataTime",1200 ));
CHECK(grib_set_double(h,"latitudeOfFirstGridPointInDegrees",10));
CHECK(grib_set_double(h,"longitudeOfFirstGridPointInDegrees",-10));
CHECK(grib_set_double(h,"latitudeOfLastGridPointInDegrees",-10));
CHECK(grib_set_double(h,"longitudeOfLastGridPointInDegrees",10));
CHECK(grib_set_double(h,"jDirectionIncrementInDegrees",0.5));
CHECK(grib_set_double(h,"iDirectionIncrementInDegrees",0.5));
/* get number of points calculated automatically by the grib_api */
CHECK(grib_get_long( h,"numberOfPointsAlongAParallel",&numberOfPointsAlongAParallel));
CHECK(grib_get_long( h,"numberOfPointsAlongAMeridian",&numberOfPointsAlongAMeridian));
numberOfPoints=numberOfPointsAlongAMeridian*numberOfPointsAlongAMeridian;
/* allocate the values array */
values=(double*)malloc(numberOfPoints*sizeof(double));
/* load the values array */
for (j=0;j<numberOfPointsAlongAMeridian;j++) {
for (i=0;i<numberOfPointsAlongAParallel;i++) {
k=i+numberOfPointsAlongAParallel*j;
values[k]=50;
}
}
/* set values in the grib */
grib_set_double_array( h,"values",values,numberOfPoints);
/* write grib to file */
f = fopen(filename,"w");
if(!f) {
perror(filename);
exit(1);
}
grib_get_message(h,&buffer,&size);
if(fwrite(buffer,1,size,f) != size) {
perror(filename);
exit(1);
}
if(fclose(f)) {
perror(filename);
exit(1);
}
grib_handle_delete( h);
return ret;
}
|
