[GRASS-user] Planet coordinate systems?

[Markus Neteler]

FYI

---------- Forwarded message ----------
From: Alessandro Frigeri <afrigeri at unipg.it>
Date: Thu, Aug 26, 2010 at 2:00 AM
Subject: Re: [GRASS-user] Planet coordinate systems?
To: Adam Dershowitz <adershowitz at exponent.com>
Cc: Markus Neteler <neteler at osgeo.org>

Hi Adam,

You hit an interesting issue.   First the good news!  You can bypass
entering epsg codes by entering proj4 declarations of the data you
want to store into GRASS.  Alternatively, you can start a new location
by selecting from the GUI (wx or tk) an existing planetary dataset
supported by GDAL/OGR, and GRASS will set up the srs for that.

As you correctly reported, epsg codes do not list planetary srs.  This
is not a big issue, as epsg is just a namespace, so basically we can
have a same code pointing to different parameters in different
namespaces.  In the last few years people working with planetary data
in gis are discussing about this, and the current namespace being used
is the IAU2000 (International Astronomical Union data from 2000).
You can have a look of different srs namespaces (including iau2000)
and relative codes at the excellent http://spatialreference.org/.

Regards,

Alessandro


PS: Markus, go on on the grass-user if you think is worth of -- I see
I'm only on grass-dev ml.