20010312: garp

>From: Stacy Brodzik <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200103130136.f2D1aFL24036

>I recently saw a garp display of most of Oregon that looked like it 
>had the major roads overlaid on the rest of the data.  Is there a roads
>overlay file?  If so, where in the gempak filetree would I find it?
>
>Thanks for your time.
>
>Stacy
>
>
>
>-- 
>Stacy Brodzik          INTERNET: address@hidden
>
>University of Washington
>Dept of Atmospheric Sciences
>Box 351640
>Seattle, WA  98195-1640
>


Stacy,
GEMPAK does come with map databases for Interstates, US highways,
State Highways and major arterials. Garp is configured to turn these
maps on automatically when you have zoomed in to a certain domain size.

The road map data bases are:

NWS supplied:
loisus.nws
loshus.nws
louhus.nws
lordus.nws

Unidata additions:
rdis.uni
rdus.uni
rdsh.uni
rdar.uni

The files are from the same sources, but the .uni mapfiles are larger since
they are created at a higher resolution.

The default in $GARPHOME/tables/maplist.tbl is to use the rdxx.uni maps when
the map area is less than 3 degrees. You can modify this interactively from
the Garp "options" menu, which has the puldown for "map backgrounds".
Once you have the map widget displayed, you can scroll down to the roads 
section.
You can modify the line color, type, style, as well as the resolution when
the map is turned on (eg 3.0 is the default) and turned off (0 is the default).

An example in maplist.tbl for using the lower resolution map files for
coarser displays and higher resolution maps for finer displays would look like:

! Byways
!
Interstate Hwys            rdis.uni             yes   3.0   0.0   2  1  2
State Hwys                 rdsh.uni             yes   3.0   0.0  23  1  1
US Hwys                    rdus.uni             yes   3.0   0.0  22  1  2
Major Arterials            rdar.uni             yes   3.0   0.0  23  1  1
!
NWS Interstates            loisus.nws           no   90.0   3.1   2  1  2
NWS US Hwys                louhus.nws           no   20.0   3.1  22  1  2
NWS State Hwys             loshus.nws           no   20.0   3.1  23  1  1
NWS Roads                  lordus.nws           no    5.0   3.1  23  1  1

Of course, you can use any of these maps in the other gempak programs as well
using the $MAPFIL program variable.


For more information on the map data bases, see the gempak online
help for mapfil, eg "phelp mapfil".

Steve Chiswell
Unidata User Support