Nancy, GEMPAK does not use its own "radar" format, but rather just reads the data from its native format, so there is not a specific "decoder" related to GEMPAK, though you might find a program which can convert the raw radar files into NetCDF files. I did provide a program "nex2img" which can be used to create a raster image of the radar data which can be used with GIS mapserver tools as Daryl Herzmann describes on his site: http://mesonet.agron.iastate.edu/docs/radmapserver/howto.html Daryl has lots of information about mapserver and the use in GIS which may be what you are looking for! Steve Chiswell Unidata User Support Ticket Details =================== Ticket ID: DDU-727620 Department: Support GEMPAK Priority: Normal Status: Closed