GEMPAK Status Report

Steve Chiswell
January 26, 2004

Purpose of GEMPAK status report

The activities carried out toward GEMPAK development and support fulfill the following endeavors as described in the Unidata 2008 NSF proposal:


Current Status

GEMPAK 5.6.M release

GEMPAK 5.6.M in progress. See the new feature summary for more information. This will be the last release to support the legacy NSAT and NMAP applications. The functionality of NSAT and NMAP is superceded by NMAP2.

GEMPAK 5.6.L.1 release

GEMPAK 5.6.L.1 encompasses many GUI and product improvement as well as decoder modifications for evolving data sets and user requirements. Additional functionality in GRIB2 encoding/decoding has been added which is currently in use for the NDFD products.

GEMPAK 5.6.L.1 Usage
Source Code 135
Linux Binary 201
FreeBSD Binary 25
Solaris Sparc Binary 23
Solaris x86 Binary 1

GEMPAK Training Workshop held October 27-29, 2003

The GEMPAK training workshop was held October 27-29, in the UCAR Center Green Complex Training Facility. This year, the training workshops were held during the Fall as a result of the Unidata summer workshop, as well as to accommodate users who traditionally are not able to attend Summer dates. There were 14 registered attendees for the GEMPAK workshop (16 is the maximum the room can accommodate).

GEMPAK 5.6.K released

New capabilities have been added to GEMPAK grid programs in support of accessing large grids including the National Digital Forecast Data Base (NDFD) 5 KM grids.

The maximum grid size that can be stored in a GEMPAK file may now be larger than the maximum number of grid points used for calculation and display purposes. To access grid files with grids larger than the maximum display limit, the grid must be subset to not exceed LLMXGD grid points. The subset can be specified using an area (GAREA) or by specifying points using a new GEMPAK parameter IJSKIP which specifies the number of points to skip in each direction and/or the beginning and ending grid point number in each direction. In addition, if the parameter is set to "YES", then it will automatically calculate the optimum skip factors to display the maximum number of grid points for the geographic region defined by the GAREA parameter. Look for the GEMPAK help on IJSKIP for additional details when available.

See the new feature summary for a description of included changes.

Radar mosaics for GIS

Iowa State is actively using GEMPAK radar mosaics with their mesonet products in GIS applications. To facilitate this process, I developed the GEMPAK program NEX2IMG to generate composite images which can be used with a file to provide GIS navigation information. Daryl Herzmann has put together a How-To document to help other sites set up their own radar mapservers.

Previous developments

See September 2003 status report for past information.

Web pages and documentation for GEMPAK 5.6 have been updated.

Ongoing Additions

COMET case studies available via CODIAC

COMET case studies are compatible with the GEMPAK/NAWIPS environment, and are being made available via the CODIAC system.

GEMPAK workshop and tutorial online

All the handouts/displays for the GEMPAK workshop are been made available through the GEMPAK web page tutorial. Included in the presentation are numerous sample exercises and output samples. This format of presentation allows workshop participants to be able to review or utilize any of the material at their home institution. The tutorial is updated as new features dictate.

The GEMPAK tutorial can be found at: