[gradsusr] Writing GrADS netCDF files with IDL

[Dave Allured]

Richard,

A control file is used with the Grads xdfopen command, but *not* the 
sdfopen command.  sdfopen is used to *directly* open a netcdf file.

   http://www.iges.org/grads/gadoc/SDFdescriptorfile.html

Use xdfopen and a control file to make up for certain missing 
metadata, such as coordinate arrays or coordinate units.  But 
hopefully you will be writing a sufficient netcdf file so that you 
do not need xdfopen.

Sorry, I do not have sample IDL code for this.  But the IDL 
documentation shows that all of the necessary functions should be 
available to write good netcdf.  There is sample code to write 
netcdf in the IDL 8.1 help system, under "NetCDF files".

If you are already creating a netcdf file from IDL, then post the 
results of ncdump -h, and we can try to tell you what's missing for 
sdfopen to work perfectly.

--Dave

On 9/13/2011 9:49 AM, Bantges, Richard J wrote:
> Hi there,
>
> I’m trying to write a GrADS compatible netCDF file using ITT’s IDL
> software, that can then be read in using GrADS’s sdfopen command.
> Does anyone have an example IDL procedure that does this please?
>
> I’ve managed to write out data in a gridded binary data file that is
> described here
> http://grads.iges.org/grads/gadoc/aboutgriddeddata.html but ideally
> I’d like to write these in netCDF format. The main problem is
> writing the netCDF so that the associated control file accurately
> describes the netCDF file content.
>
> So, if anyone has a very simple IDL procedure that writes out a
> netCDF file that can be directly read by GrADS using the sdfopen
> command that would be fantastic.