Previous: VERTICAL COORDINATES Next: GEMPAK Resource Administration Table of contents Frames User Manual GEMPAK Online Tutorial

25 GEMPAK Administration

Required Resources

The GEMPAK source distribution requires about 450MB of disk space (175MB is taken up by the map databases alone, and another 70MB resides in the bounds tables). The installed binaries add another 100-300MB or so (depending on the compiler/OS and whether the _gf and _nc programs are built). During installation, you will want extra space available as intermediate libraries are created. You should plan on having ~500MB-1.0GB total disk space available before downloading the distribution.

A minimum suggested workstation configuration would entail at least 64 or RAM. At least 256MB of swap space should be available. As model grids get bigger, and imagery is provided at higher resolution, they amount of memory required to manipulate them keeps increasing. In general however, modern workstations should be configured with much more memory and swap than these values.

For a directory schematic of the GEMPAK/NAWIPS distribution click: here.


GEMPAK and Swap Space

The most frequent problems occur with the amount of system swap space, and the number of colors used by the window manager (if 8 bit color displays are utilized). Current use suggests that you should have at least 256MB of swap space allocated on machines using the default configuration. The symptoms of not having adequate memory and swap space available will be messages resembling "Not enough memory", "Could not fork", and "Non existant executable".

The most demanding programs in terms of system resources are the grid programs. The default configuration for the maximum number of grid points allowed in a grid in the Unidata distribution is LLMXGD = 400,000 (the 12km NCEP grid #218 is comprised of 262,792 points). System memory is a factor in the number of loop windows used by GUI programs such as NMAP2.

Care should be taken if the number of gridpoints is changed, in particular if you plan on accessing the higher resolution mesoscale grids when they become available, or if you are generating large grids locally using output from models such as MM5 and WRF.

To change the maximum number of grid points, you must edit the $GEMPAK/include/gemprm.h and MCHPRM.${NA_OS} files specific to your platform. After making any changes to the files within the include directory, you must do a complete rebuild of GEMPAK, including removing the old libraries under $NAWIPS/lib/$NA_OS. Use:

make distclean

to remove all libraries and object files from the distribution source tree.


GEMPAK Colors for 8-bit displays

Most workstations have the capability to run a default display using 24-bit or TrueColor. Color allocation will not be a problem if you are running under 24-bit or TrueColor. If you must use an 8-bit default display, the following information can help you live in the limited color space.

The default number of colors for satellite images in N-AWIPS is 95. This value also effects the NPROGS. When NTL is launched it reports on the number of colors requested, and available to the system. If the system is unable to return the number of colors requested, the programs exit. You can decrease the number of colors used by nprogs by using the NTL command line options.

for example, to launch the NPROGS with only 32 colors allocated for satellite images type:

Some window systems reserve more colors for thir own use, thereby allowing programs fewer choices. If you typically experience problems with other applications getting all the colors they ask for, or if you typically have several color intensive applications such as web browsers, image viewers, and GEMPAK running at the same time, you may want to set the Maximum number of colors used by GEMPAK to a lower value. When using Netscape concurrently with GEMPAK programs, you will probably want to use the Netscape -install invokation.

To compile GEMPAK with a different number of colors used, you will need to edit the file $GEMPAK/include/colors.h:

#define GRAPH_COLORS 33   /* default graphic colors */
#define SAT_COLORS   95   /* default satellite colors */
#define RAD_COLORS   20   /* default radar colors */

25.0  GEMPAK Resource Administration
25.1  Unidata Support

 


Previous: VERTICAL COORDINATES Next: GEMPAK Resource Administration Table of contents Frames User Manual GEMPAK Online Tutorial