Dear user,

here is some information that may be useful for you to read the MODIS/MERIS .hdf files.
The files are named like this: WV_MODIS_FUB_yyyymmddhhmm.hdf (year-month-day-hour-minute)
						or:    WV_MERIS_FUB_yyyymmddhhmm.hdf
To get Latitude, Longitude and Water Vapour out of the file, you can use the programm "hdf_read_structure.pro",
which is included. This is an IDL programm, and you use it like shown below:

hdf_read_structure,outstr,file='xxx.hdf',sci_data_ok=['lon','lat','water_vapour']

What you have now is a structure in 'outstr', and you can examine the content of this structure with 'shelp, outstr'.
Notice that pixel values are set to -99 if either bad data or not cloud free.

We hope that makes it easier for you,
best regards, FUB