6.12 Get Information about a Variable from Its ID: NF90_INQUIRE_VARIABLE
NF90_INQUIRE_VARIABLE returns information about a netCDF variable
given its ID. Information about a variable includes its name, type,
number of dimensions, a list of dimension IDs describing the shape of
the variable, and the number of variable attributes that have been
assigned to the variable.
Usage
function nf90_inquire_variable(ncid, varid, name, xtype, ndims, dimids, nAtts)
integer, intent( in) :: ncid, varid
character (len = *), optional, intent(out) :: name
integer, optional, intent(out) :: xtype, ndims
integer, dimension(*), optional, intent(out) :: dimids
integer, optional, intent(out) :: nAtts
integer :: nf90_inquire_variable
ncid- NetCDF ID, from a previous call to NF90_OPEN or NF90_CREATE.
varid- Variable ID.
name- Returned variable name. The caller must allocate space for the
returned name. The maximum possible length, in characters, of a
variable name is given by the predefined constant NF90_MAX_NAME.
xtype- Returned variable type, one of the set of predefined netCDF external
data types. The type of this parameter, NF90_TYPE, is defined in the
netCDF header file. The valid netCDF external data types are NF90_BYTE,
NF90_CHAR, NF90_SHORT, NF90_INT, NF90_FLOAT, AND NF90_DOUBLE.
ndims- Returned number of dimensions the variable was defined as using. For
example, 2 indicates a matrix, 1 indicates a vector, and 0 means the
variable is a scalar with no dimensions.
dimids- Returned vector of *ndimsp dimension IDs corresponding to the
variable dimensions. The caller must allocate enough space for a
vector of at least *ndimsp integers to be returned. The maximum
possible number of dimensions for a variable is given by the
predefined constant NF90_MAX_VAR_DIMS.
natts- Returned number of variable attributes assigned to this variable.
These functions return the value NF90_NOERR if no errors
occurred. Otherwise, the returned status indicates an error. Possible
causes of errors include:
- The variable ID is invalid for the specified netCDF dataset.
- The specified netCDF ID does not refer to an open netCDF dataset.
Example
Here is an example using NF90_INQ_VAR to find out about a variable named
rh in an existing netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: status, ncid, &
RhVarId &
numDims, numAtts
integer, dimension(nf90_max_var_dims) :: rhDimIds
...
status = nf90_open("foo.nc", nf90_NoWrite, ncid)
if(status /= nf90_NoErr) call handle_error(status)
...
status = nf90_inq_varid(ncid, "rh", RhVarId)
if(status /= nf90_NoErr) call handle_err(status)
status = nf90_inquire_variable(ncid, RhVarId, ndims = numDims, natts = numAtts)
if(status /= nf90_NoErr) call handle_err(status)
status = nf90_inquire_variable(ncid, RhVarId, dimids = rhDimIds(:numDims))
if(status /= nf90_NoErr) call handle_err(status)
