This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
>From: Anthony B Tang <address@hidden> >Organization: UCAR/Unidata >Keywords: 200210011922.g91JMR118738 >Hi! > >I read on the forums that GDRADR produces grid format files for GEMpak to >display NexRad Level 3 data. However, cannot find anywhere that states exactly >how to use it. I have NEXRAD data, they are not from a stream and I'm not usin > g >LDM. The data is in several separate files and in the $RAD directory. > >When I go into GDRADR, it asks for the GDFILE, while I specify and isn't that >all that is necessary? Since all the information should be in the NEXRAD data, >why do we need to specify more? I've seen the examples on Chapter4 of the >GEMPak manual and it tells us to place different things, but am I right to say >that those examples are from streaming data? > >As of now, when I run GDRADR, it writes a small file, but then asks for more >data, which I do not know, but I think is in the NEXRAD files. > >Thanks for all your help. > >=-Anthony > >__________________________________________________ >Do you Yahoo!? >New DSL Internet Access from SBC & Yahoo! >http://sbc.yahoo.com > The output grid file is specified by GDFILE. It is created if it doesn't exist. The input NEXRAD Level III data is assumed to be found according to the NEXRIII template defined in $GEMTBL/config/datatype.tbl. The program uses the GDPFUN value to define %prod% in the template, and each station in the STNFIL will deine the %site% template. The program will try to locate the time closest RADTIM within the RADDUR window. See "phelp gdradr", and/or http://www.unidata.ucar.edu/packages/gempak/examples/gdradr/. There is nothing in gdradr particular to how you receive the data. You just have to name the directory structure for your data so that the program can use the %site% and %prod% templates in order to find the nearest matching time for each radar. Steve Chiswell