MAPGEN and GRASS

[Dave Gerdes]

> Date: Tue, 1 Jun 93 13:39:36 EDT
> From: gie at charon.er.usgs.gov (Gerald I. Evenden)
> Message-Id: <9306011739.AA22954 at charon.er.usgs.gov>
> Sender: lists-owner at max.cecer.army.mil
> Reply-To: grassu-list at max.cecer.army.mil
> Precedence: Bulk
> To: grassu-list at max.cecer.army.mil
> Subject: Re:  MAPGEN and GRASS
> 
> >From grass-lists-owner at max.cecer.army.mil Mon May 31 22:08:15 1993
> >From: Andrew Hertz <hertz at geog.psu.edu>
> >Subject: MAPGEN and GRASS
> >Date: 	Mon, 31 May 1993 21:36:03 -0400
> >Hi,
> >
> >I have several MAPGEN/GRASS questions...
> >
> >I just downloaded and installed GRASS4.1 and I noticed that
> >the mapgen and proj versions embedded within GRASS don't 
> >seem to match the most up to date stuff on charon.er.usgs.gov.
> >GRASS seems to be using mapgen version 4.0 and proj versions 3.1, 4.5, and 4.6.  On charon... is mapgen version 4.1 and proj
> >version 4.1.3.  Do you suggest getting the latest from charon
> >and using it in src.related.mapgen?  And can you explain the
> >three versions of proj in GRASS and what versions 4.5 and 4.6
> >correspond to?  
> 
> The GRASS release is a snapshot of what is current at the time when
> CERL makes up its release.  MAPGEN, consisting of the basic mapgen
> directory and graphics subsystem, has been fairly static, so the GRASS
> release should be  fairly close to charon's.
> 
> Proj, however, has been quite dynamic since the release of 4.x and thus
> CERL's release quickly goes out of date.  I expect release 4.2 to come
> out late this summer and will, among other updates, include datum
> translation procedures.
> 
> One other element that confuses charon vs. GRASS, is that charon's
> PROJ.4 is designed to be as ANSI (and now ISO, when I get some docs
> on this) as possible.  Because of CERL's current commitment to K&R
> code, they translate PROJ.4.


MAPGEN and PROJ that are distributed with GRASS were installed by the
SCS with their value added GRASS-MAPGEN interface.  The versions
of MAPGEN and PROJ have not been updated for fear of breaking the 
GRASS-MAPGEN interface.  So what is there is the same that was 
released with GRASS 4.0.

As for ANSI vs. K&R,  on a completely separate track, we used the proj
library with some code that SCS contributed, and have provided integrated
projection support within GRASS 4.1.  To do that, we had to take
the latest version of the proj library  (well it was latest a few months back)
and convert it to K&R and installed it as a library in GRASS.  This
copy of the library has nothing to do with the GRASS-MAPGEN interface.



-- 
  David Gerdes
  US Army Construction Engineering Research Lab
  Spatial Analysis & Systems Team
  d-gerdes at cecer.army.mil