[GRASSLIST:567] Re: set up grass location

[Maciek Sieczka]

On Tue, 4 Apr 2006 11:32:31 +0100
"Ana Soares" <tiobrothercamarada at gmail.com> wrote:

> Hello :)
> 
> Is there any way to set up a new grass location (with all those
> fields : coordinate system, etc) without using the terminal ?

For 6.x, using EPSG codes if Grass is started GUI mode.

Another option is to setup a quick'n'dirty XY location and use g.proj
to modify the projection, eg. by PROJ.4 syntax or a file with WKT
projection definition (RTM for details).

> I mean, is there (and if there is, what is it) any structure where
> grass keeps this info so that I can enter it ? I know it uses
> environment variables, but I don't know
> what to do for the fields like coordinate system, datum, etc

Grass depends on PROJ.4 for projections handling.

Read cs2cs man to learn how to get the names it uses.

Check epsg and esri files in the directory where your PROJ.4 is
installed for some complete cordinate systems strings.

Proj.4 naming is 90% compatible with Grass, but:

PROJ.4			Grass
latlong			ll
krass			krassovsky


Propably more like these, but only these I know.


Also, PROJ.4 needs uppercase ellipsoids names, while Grass tolerates
both lower and uppercase.

Then check projections, ellipse.table and datum.table in the
dir where_your_grass_lives/etc/. Seems they are not complete, but will
give you some further insight.

It's all a bit mess but that's the way it is for now, due to legacy
reasons.

Maciek

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