[GRASSLIST:2181] Re: Projection questions

Rich Shepard rshepard at appl-ecosys.com
Fri Jul 27 14:05:02 EDT 2001

On Fri, 27 Jul 2001, Frank Warmerdam wrote:

> Right, but it might be because of GDAL itself.  I am not sure, and would have
> to look into it in some detail which I don't have time for this afternoon.


  No rush on my part, as long as I understand what's happening and the data
are properly converted.

> A "location" called PERMANENT?  That would seem to be very confusing given the
> convention of calling the primary mapset within a locatin PERMANENT.  Why not
> a location called "pnw" (Pacific North West) with a PERMANENT mapset?

  Ah! I thought that it was the primary location that was so named. While
I'm NOT advocating doing anything about this now, IMO it is one of the prime
candidates for replacement in the next major revision. But, that's a
discussion for another time, place and thread.

  OK. It's still in the earliest stages of reorganization, so I'll move
stuff around. Then, PERMANENT/ will be on the same directory level as the
states in which I have projects, and each project within a state will be a
level below that. Works for me, as long as it works for GRASS. :-)

> 99 - other
> 99 is basically the catchall for generic projections support.  Only UTM,
> Lat/Long and Unknown (and perhaps state plane?) are handled otherwise.  This
> has to do with how the software evolved.

  I understand the path that lead us here, and I am just trying to
understand the why of it. This, too, is something to totally revise down the
road. BTW, state plane falls in with "other", too. Because I don't know how
these catagories are used in the modules, it is difficult to fully
comprehend the details.

> This seems like a big questions.  I don't know how pervasive use of PROJ_INFO
> is in the various GRASS commands.  Some get all the information they need from
> the WIND files.

  Yes, another evolutionary diversion where the branches split, and we're
tying them together with string, eh? Ah, consistency! :-)

Many, many thanks Frank!


Dr. Richard B. Shepard, President

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