MAPGEN

[Jill Schuler]

%%%----- Begin Included Message -----
%%%%
%%%Our version of Mapgen4.1 will not work when we
%%%are using a Latitude and Longitude Projection.
%%%
%%%The following text demonstrates the process going into the
%%%interface.
%%%
%%%When setting up the location we responded to
%%%the question concerning ellipsoid as sphere.
%%%This is what the DEFAULT_WIND looks like:
%%%rncrds0:34> more DEFAULT_WIND
%%%proj:       3
%%%zone:       0
%%%north:      33N
%%%south:      32:52:30N
%%%east:       92:45W
%%%west:       92:52:30W
%%%cols:       2500
%%%rows:       2813
%%%e-w resol:  0:00:00.18
%%%n-s resol:  0:00:00.159972
%%%
%%%Creating PROJ_INFO & PROJ_UNITS with
%%%g.setproj works fine, here are the PROJ_INFO & PROJ_UNITS file:
%%%
%%%rncrds0:35> more PROJ_INFO
%%%name: Latitude-Longitude
%%%proj: ll
%%%ellps: sphere
%%%
%%%rncrds0:36> more PROJ_UNITS
%%%unit: degree
%%%units: degrees
%%%meters: 1.0
%%%
%%%When going to mapgen for the first time with
%%%An error occurs, which allows us to go no furthur:
%%%
%%%The PROJ_INFO file for Location <long_lat_test> 
%%%is not in the correct format.
%%%Please run the command g.setproj from the PERMANENT mapset.
%%%EXITING ..........................................
%%%
%%%Is it possible that our errors come from the way the software
%%%was loaded onto our system?
%%%
%%%
%%%We would also like to know if there is a driver for either
%%%the Calcomp 1044 or the Calcomp 5800 Series Plotters for 
%%%mapgen4.1 .
%%%
%%%----- End Included Message -----

> The MAPGEN documentation states that g.setproj should add '"es" or "e"
> and "a" values' to the PROJ_INFO file.  However, it does not.
> 

Unfortunately, at SCS we very seldom use the LL projection.  
When I revised the mapgen4.1 script for compatibility with Jerry's 
mapgen4.0, I assumed incorrectly that all PROJ_INFO files would record 
the same information.  Other projection's PROJ_INFO files set a and es 
ellipsoid parameter values.
 
The LL PROJ_INFO file does not record this information.  
If you must work in LL then manually add the es and a values to the 
PROJ_INFO file.  The values and format for the PROJ_INFO file are:

name: Latitude-Longitude
proj: ll
ellps: sphere
a:6370997.0
e:0.0

The 4.12 mapgen interface is not fully functional with a LL mapset.  You
will not be able to use the make.fill command in lat/long.


Give me a buzz back if you have any more problems.

Sincerely,

Jill

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#  # #### #### ####      ######  #### ##### Jill R. Schuler
#  # #    #  # #  #      #      #     #     USDA 
#  # #### #  # #### ### ####   #     ####   Soil Conservation Service
#  #    # #  # #  #        #  #         #   National Cartography and 
#  #    # #  # #  #       #  #         #    GIS Center
#### #### #### #  #   ####  ###### ####     P.O. Box 6567 
				            Ft. Worth, TX 76115
e-mail: jschuler at ncg.scs.ag.gov             Phone: (817) 334-5559 x3086

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