mirror of
https://github.com/Unidata/netcdf-c.git
synced 2024-12-09 08:11:38 +08:00
164 lines
5.6 KiB
C
164 lines
5.6 KiB
C
/* Copyright 2018 University Corporation for Atmospheric
|
|
Research/Unidata. See COPYRIGHT file for conditions of use. */
|
|
/**
|
|
* @file
|
|
* @ingroup tutorial
|
|
* This is part of the netCDF package.
|
|
*
|
|
* This is a simple example which writes and then reads some surface
|
|
* pressure and temperatures, and stores additional metadata as
|
|
* dimension variables, and an attribute with a nice poem about data.
|
|
*
|
|
* @author Ed Hartnett started 2006/03/25, finished 2019/7/2
|
|
*/
|
|
#include <netcdf.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#define FILE_NAME "sfc_pres_temp_more.nc"
|
|
#define NDIMS 2
|
|
#define LAT_NAME "latitude"
|
|
#define LAT_LEN 40
|
|
#define LON_NAME "longitude"
|
|
#define LON_LEN 80
|
|
#define PRES_NAME "surface_pressure"
|
|
#define TEMP_NAME "surface_temperature"
|
|
#define SONNET_NAME "Brownings_sonnet_mangled_by_Hartnett"
|
|
|
|
char poem[] = "How do I love data? Let me count the ways.\n"
|
|
"I love data to the depth and breadth and height\n"
|
|
"My model can reach, when running overnight\n"
|
|
"From the ends of CONUS and ideal Space.\n"
|
|
"I love data to the level of every day's\n"
|
|
"6Z ob, by Sun and Linux box.\n"
|
|
"I love data freely, as PIs strive for funding;\n"
|
|
"I love data purely, as good C code is compiled,\n"
|
|
"I love data with the passion put to use\n"
|
|
"In my old programs, and with my childhood's TRS-80.\n"
|
|
"I love data with a love I seemed to lose\n"
|
|
"With my lost password -I love data with the constants,\n"
|
|
"expressions, statements, of all my code! -and, if NSF choose,\n"
|
|
"I shall love data better after processing.";
|
|
|
|
int
|
|
main()
|
|
{
|
|
int ncid, lon_dimid, lat_dimid, pres_varid, temp_varid, lat_varid, lon_varid;
|
|
int dimids[NDIMS];
|
|
float pres_out[LAT_LEN][LON_LEN], pres_in[LAT_LEN][LON_LEN];
|
|
float temp_out[LAT_LEN][LON_LEN], temp_in[LAT_LEN][LON_LEN];
|
|
float latitude[LAT_LEN], longitude[LON_LEN];
|
|
char *att_in;
|
|
size_t len_in;
|
|
int error = 0;
|
|
int lat, lon, retval;
|
|
|
|
/* Create phoney data. If this wasn't an example program, we would
|
|
* have some real data to write, for example, model output. */
|
|
for (lat = 0; lat < LAT_LEN; lat++)
|
|
for (lon = 0; lon < LON_LEN; lon++)
|
|
{
|
|
pres_out[lat][lon] = 1013.1;
|
|
temp_out[lat][lon] = 12.5;
|
|
}
|
|
|
|
/* These are the latitudes and longitudes which correspond with
|
|
* ticks on the dimension axes. */
|
|
for (lat = 0; lat < LAT_LEN; lat++)
|
|
latitude[lat] = 40. + lat * 2.5;
|
|
for (lon = 0; lon < LON_LEN; lon++)
|
|
longitude[lon] = -90. - lon * 5;
|
|
|
|
/* Create the file. */
|
|
if ((retval = nc_create(FILE_NAME, NC_CLOBBER, &ncid)))
|
|
return retval;
|
|
|
|
/* Add data sonnet. By using NC_GLOBAL we mean that this attribute
|
|
* applies to the entire file, not just to one variable. Don't
|
|
* forget that strlen does not include the null terminator, so if
|
|
* you want it, you need to add one more byte. */
|
|
if ((retval = nc_put_att_text(ncid, NC_GLOBAL, SONNET_NAME,
|
|
strlen(poem) + 1, poem)))
|
|
return retval;
|
|
|
|
/* Define the dimensions. */
|
|
if ((retval = nc_def_dim(ncid, LAT_NAME, LAT_LEN, &lat_dimid)))
|
|
return retval;
|
|
if ((retval = nc_def_dim(ncid, LON_NAME, LON_LEN, &lon_dimid)))
|
|
return retval;
|
|
|
|
/* Save the dimension information, in variables of the same
|
|
* name. First we need to define these variables. */
|
|
dimids[0] = lat_dimid;
|
|
if ((retval = nc_def_var(ncid, LAT_NAME, NC_FLOAT, 1, dimids, &lat_varid)))
|
|
return retval;
|
|
dimids[0] = lon_dimid;
|
|
if ((retval = nc_def_var(ncid, LON_NAME, NC_FLOAT, 1, dimids, &lon_varid)))
|
|
return retval;
|
|
|
|
/* Define the variables. */
|
|
dimids[0] = lat_dimid;
|
|
dimids[1] = lon_dimid;
|
|
if ((retval = nc_def_var(ncid, PRES_NAME, NC_FLOAT, NDIMS, dimids, &pres_varid)))
|
|
return retval;
|
|
if ((retval = nc_def_var(ncid, TEMP_NAME, NC_FLOAT, NDIMS, dimids, &temp_varid)))
|
|
return retval;
|
|
|
|
/* End define mode. */
|
|
if ((retval = nc_enddef(ncid)))
|
|
return retval;
|
|
|
|
/* Write the dimension metadata. */
|
|
if ((retval = nc_put_var_float(ncid, lat_varid, latitude)))
|
|
return retval;
|
|
if ((retval = nc_put_var_float(ncid, lon_varid, longitude)))
|
|
return retval;
|
|
|
|
/* Write the phoney data. */
|
|
if ((retval = nc_put_var_float(ncid, pres_varid, (float *)pres_out)))
|
|
return retval;
|
|
if ((retval = nc_put_var_float(ncid, temp_varid, (float *)temp_out)))
|
|
return retval;
|
|
|
|
/* Close the file. */
|
|
if ((retval = nc_close(ncid)))
|
|
return retval;
|
|
|
|
/* Open the file and check that everything's OK. */
|
|
if ((retval = nc_open(FILE_NAME, 0, &ncid)))
|
|
return retval;
|
|
|
|
/* Read the attribute. First find it's length to allocate storage
|
|
* for it. */
|
|
if ((retval = nc_inq_attlen(ncid, NC_GLOBAL, SONNET_NAME, &len_in)))
|
|
return retval;
|
|
if (!(att_in = malloc(len_in)))
|
|
return NC_ENOMEM;
|
|
if ((retval = nc_get_att_text(ncid, NC_GLOBAL, SONNET_NAME, att_in)))
|
|
return retval;
|
|
if (strcmp(att_in, poem))
|
|
error++;
|
|
free(att_in);
|
|
if (error)
|
|
return -2;
|
|
|
|
/* Read the data. */
|
|
if ((retval = nc_get_var_float(ncid, pres_varid, (float *)pres_in)))
|
|
return retval;
|
|
if ((retval = nc_get_var_float(ncid, temp_varid, (float *)temp_in)))
|
|
return retval;
|
|
|
|
/* Check the data. */
|
|
for (lat = 0; lat < LAT_LEN; lat++)
|
|
for (lon = 0; lon < LON_LEN; lon++)
|
|
if (pres_in[lat][lon] != pres_out[lat][lon] ||
|
|
temp_in[lat][lon] != temp_out[lat][lon])
|
|
return -2;
|
|
|
|
/* Close the file. */
|
|
if ((retval = nc_close(ncid)))
|
|
return retval;
|
|
|
|
return 0;
|
|
}
|