How to use an 'HDF format' data file in GrADS

[C. Shaji]

Dear All,
I am resubmitting this query since I haven't received any reply to my
previous email. I am using GrADS v1.9b4 on a SunOS 1 5.9 platform.

I would like to know how can I load and plot the variables from an HDF
format data file in GrADS. I haven't used this type of data file earlier.
I ran GrADS by using 'gradshdf' command. Then I used sdfopen and xdfopen
commands to load the data file. But both failed as shown below.

ga-> sdfopen month01_combined.hdf
Scanning self-describing file:  month01_combined.hdf
SDF file has no discernable X coordinate.

ga-> xdfopen month01_combined.hdf
Scanning Descriptor File:  month01_combined.hdf
XDFOpen Error:  Unknown keyword in description file
  --> The invalid description file record is:
  --> q?
  The data file was not opened.

If anybody is familiar with handling 'HDF' format data file in GrADS,
please give me some useful tips.

Also is there any command similar to ncdump to know the metadata
information from the hdf file? When I use ncdump, I get the following
error.

access1 41% ncdump -h month01_combined.hdf
ncdump: month01_combined.hdf: Not a netCDF fil

Thanks in advance.

C. Shaji.