[gradsusr] Opening hdf files

[James Ciarlo`]

dear gradsusr,

I have a few hdf files (below) I would like to open with grads, but I am
finding difficulty using the xdfopen function.

SEVIRI_latitude.raw
SEVIRI_longitude.raw
SEVIRI_readme.txt
mean_seviri_aer_oc_d3_tau550_Aug2005.hdf
mean_seviri_aer_oc_d3_tau550_Dec2005.hdf
mean_seviri_aer_oc_d3_tau550_Jul2005.hdf
mean_seviri_aer_oc_d3_tau550_Jun2005.hdf
mean_seviri_aer_oc_d3_tau550_Nov2005.hdf
mean_seviri_aer_oc_d3_tau550_Oct2005.hdf
mean_seviri_aer_oc_d3_tau550_Sep2005.hdf


I tried to construct a descriptor file but cannot figure out how to access
the information for the coordinates:

DSET mean_seviri_aer_oc_d3_tau550_Aug2005.hdf
TITLE monthly average of the daily total aerosol optical depth at 550 nm
derived from MSG/SEVIRI
UNDEF 99999.0
XDEF dimension1 ? LINEAR ? ?
YDEF dimension2  ? LINEAR ? ?
TDEF dimension3 ? LINEAR ? ?
VARS 1
Aerosol_optical_depth=>aod 1 99 aerosol optical depth
ENDVARS

I don't even know if I am on the right track. Can someone help me get to an
answer please? because I am not managing to follow the help on GrADS index.

I have also attached the text file with the remaining information

Regards,

James
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The hdf product is the monthly average of the daily total aerosol optical depth at 550 nm derived from MSG/SEVIRI. Note that it's not only minearal dust. Corresponding images are provided.

Format of SEVIRI latitude et longitude .raw files: binary, float-32, without header, size 3712x3712.

Values give latitude and longitude of each pixel centre of the MSG/SEVIRI full resolution window.

The Mediterranean window position is defined by
rowN rowS colW colE: 356 956 1606 2856.