ncvar_rename: Rename an Existing Variable in a netCDF File

In ncdf4: Interface to Unidata netCDF (Version 4 or Earlier) Format Data Files

Rename an Existing Variable in a netCDF File

Description

Renames an existing variable that currently is part of a netCDF file that is on disk.

Usage

 ncvar_rename( nc, old_varname, new_varname, verbose=FALSE )

Arguments

nc	The already-existing netCDF file that we want to manipulate. This must be a value of class "ncdf4" returned by a call to nc_open(...,write=TRUE).
old_varname	The variable in the file that is to be renamed. This can be a string with the name of the variable to be renamed, or a value of class "ncvar4" returned by a call to ncvar_def().
new_varname	A string containing the new name of the variable.
verbose	If true, run verbosely.

Details

This call allows you to rename a variable that already exists in a netCDF file.

NOTE that the return value of this routine should replace the old netCDF file handle that you were using. This newly returned value reflects the modifications to the file that were accomplished by calling this routine.

Value

The updated value of nc that contains the new name. This needs to replace the old value of nc in the code. I..e, ncid <- ncvar_rename( ncid, ... ).

Author(s)

David W. Pierce [e-mail]

References

http://dwpierce.com/software

See Also

ncdim_def, nc_create, ncvar_def.

Examples

## Not run: 
#===================================================================
# PART 1.  MAKE A TEST NETCDF FILE THAT WE WILL MANIPULATE IN PART 2
#===================================================================

#----------------
# Make dimensions
#----------------
xvals <- 1:360
yvals <- -90:90

nx <- length(xvals)
ny <- length(yvals)

xdim <- ncdim_def( 'Lon', 'degreesE', xvals )
ydim <- ncdim_def( 'Lat', 'degreesE', yvals )
tdim <- ncdim_def( 'Time', 'days since 1900-01-01', 0, unlim=TRUE )

#---------
# Make var
#---------
mv <- 1.e30     # missing value
var_temp <- ncvar_def( 'Temperature', 'K', list(xdim,ydim,tdim), mv )

#---------------------
# Make new output file
#---------------------
output_fname <- 'test_real3d.nc'
ncid_new <- nc_create( output_fname, list(var_temp))

#-------------------------------
# Put some test data in the file
#-------------------------------
data_temp <- array(0.,dim=c(nx,ny,1))
for( j in 1:ny )
for( i in 1:nx )
        data_temp[i,j,1] <- sin(i/10)*sin(j/10)

ncvar_put( ncid_new, var_temp, data_temp, start=c(1,1,1), count=c(nx,ny,1))

#--------------------------
# Close our new output file
#--------------------------
nc_close( ncid_new )

#===========================================================================
# PART 2.  RENAME A NEW VARIABLE TO THE FILE
#===========================================================================

#-------------------------------------------------
# Open the existing file we're going to manipulate
#-------------------------------------------------
ncid_old <- nc_open( output_fname, write=TRUE )

old_varname <- 'Temperature'
new_varname <- 'T'

ncid_old <- ncvar_rename( ncid_old, old_varname, new_varname )

print(ncid_old)

nc_close( ncid_old )

# Clean up our example
file.remove( output_fname )

## End(Not run)

ncdf4 documentation built on Sept. 11, 2024, 8:16 p.m.