NetCDF
4.3.2
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Dimension functions. More...
#include "ncdispatch.h"
Go to the source code of this file.
Functions | |
int | nc_def_dim (int ncid, const char *name, size_t len, int *idp) |
Define a new dimension. | |
int | nc_inq_dimid (int ncid, const char *name, int *idp) |
Find the ID of a dimension from the name. | |
int | nc_inq_dim (int ncid, int dimid, char *name, size_t *lenp) |
Find the name and length of a dimension. | |
int | nc_rename_dim (int ncid, int dimid, const char *name) |
Rename a dimension. | |
int | nc_inq_ndims (int ncid, int *ndimsp) |
Find the number of dimensions. | |
int | nc_inq_unlimdim (int ncid, int *unlimdimidp) |
Find the ID of the unlimited dimension. | |
int | nc_inq_dimname (int ncid, int dimid, char *name) |
Find out the name of a dimension. | |
int | nc_inq_dimlen (int ncid, int dimid, size_t *lenp) |
Find the length of a dimension. |
Dimension functions.
These functions define and inquire about dimensions.
Copyright 2010 University Corporation for Atmospheric Research/Unidata. See COPYRIGHT file for more info.
Definition in file ddim.c.
int nc_def_dim | ( | int | ncid, |
const char * | name, | ||
size_t | len, | ||
int * | idp | ||
) |
Define a new dimension.
The function nc_def_dim adds a new dimension to an open netCDF dataset in define mode. It returns (as an argument) a dimension ID, given the netCDF ID, the dimension name, and the dimension length. At most one unlimited length dimension, called the record dimension, may be defined for each classic or 64-bit offset netCDF dataset. NetCDF-4 datasets may have multiple unlimited dimensions.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
name | Name of the dimension to be created. |
len | Length of the dimension to be created. Use NC_UNLIMITED for unlimited dimensions. |
idp | Pointer where dimension ID will be stored. |
NC_NOERR | No error. |
Here is an example using nc_def_dim() to create a dimension named lat of length 18 and a unlimited dimension named rec in a new netCDF dataset named foo.nc:
#include <netcdf.h> ... int status, ncid, latid, recid; ... status = nc_create("foo.nc", NC_NOCLOBBER, &ncid); if (status != NC_NOERR) handle_error(status); ... status = nc_def_dim(ncid, "lat", 18L, &latid); if (status != NC_NOERR) handle_error(status); status = nc_def_dim(ncid, "rec", NC_UNLIMITED, &recid); if (status != NC_NOERR) handle_error(status);
int nc_inq_dim | ( | int | ncid, |
int | dimid, | ||
char * | name, | ||
size_t * | lenp | ||
) |
Find the name and length of a dimension.
The length for the unlimited dimension, if any, is the number of records written so far.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
dimid | Dimension ID, from a previous call to nc_inq_dimid() or nc_def_dim(). |
name | Returned dimension name. The caller must allocate space for the returned name. The maximum possible length, in characters, of a dimension name is given by the predefined constant NC_MAX_NAME. (This doesn't include the null terminator, so declare your array to be size NC_MAX_NAME+1). The returned character array will be null-terminated. |
lenp | Pointer to location for returned length of dimension. For the unlimited dimension, this is the number of records written so far. |
Here is an example using nc_inq_dim() to determine the length of a dimension named lat, and the name and current maximum length of the unlimited dimension for an existing netCDF dataset named foo.nc:
#include <netcdf.h> ... int status, ncid, latid, recid; size_t latlength, recs; char recname[NC_MAX_NAME+1]; ... status = nc_open("foo.nc", NC_NOWRITE, &ncid); if (status != NC_NOERR) handle_error(status); status = nc_inq_unlimdim(ncid, &recid); if (status != NC_NOERR) handle_error(status); ... status = nc_inq_dimid(ncid, "lat", &latid); if (status != NC_NOERR) handle_error(status); status = nc_inq_dimlen(ncid, latid, &latlength); if (status != NC_NOERR) handle_error(status); status = nc_inq_dim(ncid, recid, recname, &recs); if (status != NC_NOERR) handle_error(status);
int nc_inq_dimid | ( | int | ncid, |
const char * | name, | ||
int * | idp | ||
) |
Find the ID of a dimension from the name.
The function nc_inq_dimid returns (as an argument) the ID of a netCDF dimension, given the name of the dimension. If ndims is the number of dimensions defined for a netCDF dataset, each dimension has an ID between 0 and ndims-1.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
name | Name of the dimension. |
idp | Pointer where dimension ID will be stored. |
int nc_inq_dimlen | ( | int | ncid, |
int | dimid, | ||
size_t * | lenp | ||
) |
Find the length of a dimension.
The length for the unlimited dimension, if any, is the number of records written so far.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
dimid | Dimension ID, from a previous call to nc_inq_dimid() or nc_def_dim(). |
lenp | Pointer where the length will be stored. |
Here is an example using nc_inq_dim() to determine the length of a dimension named lat, and the name and current maximum length of the unlimited dimension for an existing netCDF dataset named foo.nc:
#include <netcdf.h> ... int status, ncid, latid, recid; size_t latlength, recs; char recname[NC_MAX_NAME+1]; ... status = nc_open("foo.nc", NC_NOWRITE, &ncid); if (status != NC_NOERR) handle_error(status); status = nc_inq_unlimdim(ncid, &recid); if (status != NC_NOERR) handle_error(status); ... status = nc_inq_dimid(ncid, "lat", &latid); if (status != NC_NOERR) handle_error(status); status = nc_inq_dimlen(ncid, latid, &latlength); if (status != NC_NOERR) handle_error(status); status = nc_inq_dim(ncid, recid, recname, &recs); if (status != NC_NOERR) handle_error(status);
int nc_inq_dimname | ( | int | ncid, |
int | dimid, | ||
char * | name | ||
) |
Find out the name of a dimension.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
dimid | Dimension ID, from a previous call to nc_inq_dimid() or nc_def_dim(). |
name | Returned dimension name. The caller must allocate space for the returned name. The maximum possible length, in characters, of a dimension name is given by the predefined constant NC_MAX_NAME. (This doesn't include the null terminator, so declare your array to be size NC_MAX_NAME+1). The returned character array will be null-terminated. Ignored if NULL. |
Here is an example using nc_inq_dim() to determine the length of a dimension named lat, and the name and current maximum length of the unlimited dimension for an existing netCDF dataset named foo.nc:
#include <netcdf.h> ... int status, ncid, latid, recid; size_t latlength, recs; char recname[NC_MAX_NAME+1]; ... status = nc_open("foo.nc", NC_NOWRITE, &ncid); if (status != NC_NOERR) handle_error(status); status = nc_inq_unlimdim(ncid, &recid); if (status != NC_NOERR) handle_error(status); ... status = nc_inq_dimid(ncid, "lat", &latid); if (status != NC_NOERR) handle_error(status); status = nc_inq_dimlen(ncid, latid, &latlength); if (status != NC_NOERR) handle_error(status); status = nc_inq_dim(ncid, recid, recname, &recs); if (status != NC_NOERR) handle_error(status);
int nc_inq_ndims | ( | int | ncid, |
int * | ndimsp | ||
) |
Find the number of dimensions.
In a classic model netCDF file, this funtion returns the number of defined dimensions. In a netCDF-4/HDF5 file, this function returns the number of dimensions available in the group specified by ncid, which may be less than the total number of dimensions in a file. In a netCDF-4/HDF5 file, dimensions are in all sub-groups, sub-sub-groups, etc.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
ndimsp | Pointer where number of dimensions will be written. Ignored if NULL. |
int nc_inq_unlimdim | ( | int | ncid, |
int * | unlimdimidp | ||
) |
Find the ID of the unlimited dimension.
This function finds the ID of the unlimited dimension. For netCDF-4/HDF5 files (which may have more than one unlimited dimension), the ID of the first unlimited dimesnion is returned. For these files, nc_inq_unlimdims() will return all the unlimited dimension IDs.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
unlimdimidp | Pointer where unlimited dimension ID will be stored. If there is no unlimited dimension, -1 will be stored here. Ignored if NULL. |
int nc_rename_dim | ( | int | ncid, |
int | dimid, | ||
const char * | name | ||
) |
Rename a dimension.
This function renames an existing dimension in a netCDF dataset open for writing. You cannot rename a dimension to have the same name as another dimension.
For netCDF classic and 64-bit offset files, if the new name is longer than the old name, the netCDF dataset must be in define mode.
For netCDF-4 files the dataset is switched to define more for the rename, regardless of the name length.
ncid | NetCDF or group ID, from a previous call to nc_open(), nc_create(), nc_def_grp(), or associated inquiry functions such as nc_inq_ncid(). |
dimid | Dimension ID, from a previous call to nc_inq_dimid() or nc_def_dim(). |
name | New name for dimension. Must be a null-terminated string with length less than NC_MAX_NAME. |
Here is an example using nc_rename_dim to rename the dimension lat to latitude in an existing netCDF dataset named foo.nc:
#include <netcdf.h> ... int status, ncid, latid; ... status = nc_open("foo.nc", NC_WRITE, &ncid); if (status != NC_NOERR) handle_error(status); ... status = nc_redef(ncid); if (status != NC_NOERR) handle_error(status); status = nc_inq_dimid(ncid, "lat", &latid); if (status != NC_NOERR) handle_error(status); status = nc_rename_dim(ncid, latid, "latitude"); if (status != NC_NOERR) handle_error(status); status = nc_enddef(ncid); if (status != NC_NOERR) handle_error(status);