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 Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated.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.
Michael, The section 2 setting up realtime LDM data for GEMPAK has the link: http://www.unidata.ucar.edu/software/gempak/GEMPAK/configuration.html This explains how to create the LDM pqact entries for your LDM which among other things will create decoder entries for model data received by LDM so that you can use programs like GDCROSS on realtime data. You do not have to do this just to run GEMPAK if you already have GEMPAK gridded data files that you want to look at. This step is just for receiving realtime IDD data via the LDM for use with GEMPAK. When editing the Gemenviron (Gemenviron.profile) file, GEMDATA is the directory where the realtime data will be arriving from the LDM, eg LDMHOME/data/gempak. In general, the LDM pqact.conf decoder entries will write relative to the LDMHOME installation, and create data under the LDM's data/gempak directory. The GEMDATA variable is used to find the realtime data on your system (in particular, the GUI applications need this). You can always run command line programs (like GDCROSS) and specify the complete path to data, or use on a local directory data file. By defining the GEMDATA location for a directory tree, the package will have a consistent configuration so that the programs are configured to look for data where the LDM is storing it so that you can say "GDFILE=nam" for instance, and the program will find the current nam model data set for plotting (under $GEMDATA/model/eta/YYYYMMDDHH_eta211.gem). Steve Chiswell Unidata User Support > Institution: Lyndon State College > Package Version: 5.9.2 > Operating System: Red Hat Linux Enterprise 4 > Hardware Information: Dell Dimension 4600 > Inquiry: I have unpacked the binary distribution. I am now on step 2 of this : > > Runtime Configuration > > 1. > > Create a symbolic link to your current version > > The top level ($NAWIPS) directory of the version you just installed is > /home/gempak/GEMPAKversion. You should create a symbolic link in the > /home/gempak directory from GEMPAKversion to a directory called NAWIPS with > > ln -s GEMPAKversion NAWIPS > > By creating the link, users can configure their .cshrc/.profile entries to > source the /home/gempak/NAWIPS/Gemenviron[.profile] files without being > modified when a new distribution is installed. Also, this allows the > administrator to build and install a new version without interrupting current > users. If you have a version of GEMPAK currently in use, remove the current > /home/gempak/NAWIPS link and relink using the command above when you are > ready for users to begin using the new release of GEMPAK. > 2. > > Setup your local data directories and decoders > > Once you have your distribution installed, setup your LDM decoders, and > define your data directories in Gemenviron[.profile]. See the GEMPAK tutorial > for information on setting up the N-PROGS and Garp. Pattern/Action examples > for the LDM pqact.conf can be generated by typing > $NAWIPS/ldm/etc/gen_pqact.csh. The gen_pqact.csh script will create a > pqact.gempak files(s) in your current working directory where the paths > appropriate to your $GEMPAK and $GEMTBL variables have been inserted. Copy or > link the GEMPAK "dc" decoders from $GEMEXE into your ~ldm/decoders directory > (the gen_pqact.csh script assumes the LDM will find your decoders under its > decoders/ relative directory. > > > > Step 2 seems a little vague to me. I was wondering if you could possibly > explain step by step how to setup the Gemenviron.profile and Gemenviron > files. I have opened these files and tried to understand the comments within > the files, but still cannot pinpoint what to do. Also, is this the last step > before I can run programs such as GDCROSS? I have used Gempak extensively but > have never installed it. Thank you for any help. > > > > Ticket Details =================== Ticket ID: VHA-648685 Department: Support GEMPAK Priority: High Status: Closed