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92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
/** \file
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Write the simple_xy file, with some of the features of netCDF-4.
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This is a very simple example which is based on the simple_xy example,
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but whch uses netCDF-4 features, such as compression. Please see the
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simple_xy example to learn more about the netCDF-3 API.
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Like simple_xy_wr.c, this program writes a 2D netCDF variable (called
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"data") and fills it with sample data. It has two dimensions, "x" and
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"y".
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Full documentation for netCDF can be found at:
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http://www.unidata.ucar.edu/netcdf/docs
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <netcdf.h>
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/* This is the name of the data file we will create. */
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#define FILE_NAME "simple_xy_nc4.nc"
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/* We are writing 2D data, a 6 x 12 grid. */
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#define NDIMS 2
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#define NX 6
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#define NY 12
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/* Handle errors by printing an error message and exiting with a
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* non-zero status. */
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#define ERRCODE 2
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#define ERR(e) {printf("Error: %s\n", nc_strerror(e)); exit(ERRCODE);}
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int
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main()
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{
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int ncid, x_dimid, y_dimid, varid;
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int dimids[NDIMS];
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size_t chunks[NDIMS];
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int shuffle, deflate, deflate_level;
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int data_out[NX][NY];
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int x, y, retval;
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/* Set chunking, shuffle, and deflate. */
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shuffle = NC_SHUFFLE;
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deflate = 1;
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deflate_level = 1;
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/* Create some pretend data. If this wasn't an example program, we
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* would have some real data to write, for example, model output. */
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for (x = 0; x < NX; x++)
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for (y = 0; y < NY; y++)
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data_out[x][y] = x * NY + y;
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/* Create the file. The NC_NETCDF4 parameter tells netCDF to create
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* a file in netCDF-4/HDF5 standard. */
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if ((retval = nc_create(FILE_NAME, NC_NETCDF4, &ncid)))
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ERR(retval);
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/* Define the dimensions. */
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if ((retval = nc_def_dim(ncid, "x", NX, &x_dimid)))
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ERR(retval);
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if ((retval = nc_def_dim(ncid, "y", NY, &y_dimid)))
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ERR(retval);
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/* Set up variable data. */
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dimids[0] = x_dimid;
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dimids[1] = y_dimid;
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chunks[0] = NX/4;
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chunks[1] = NY/4;
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/* Define the variable. */
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if ((retval = nc_def_var(ncid, "data", NC_INT, NDIMS,
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dimids, &varid)))
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ERR(retval);
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if ((retval = nc_def_var_chunking(ncid, varid, 0, &chunks[0])))
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ERR(retval);
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if ((retval = nc_def_var_deflate(ncid, varid, shuffle, deflate,
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deflate_level)))
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ERR(retval);
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/* No need to explicitly end define mode for netCDF-4 files. Write
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* the pretend data to the file. */
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if ((retval = nc_put_var_int(ncid, varid, &data_out[0][0])))
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ERR(retval);
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/* Close the file. */
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if ((retval = nc_close(ncid)))
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ERR(retval);
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printf("*** SUCCESS writing example file simple_xy_nc4.nc!\n");
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return 0;
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}
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