[GRASS5] GRASS 5.3/5.7, GDAL and southern hemisphere

[Paul Kelly]

On Thu, 25 Sep 2003, Markus Neteler wrote:

> WARNING: [tuc6] in mapset [tucuman] - in different zone [-4] than current
>          region [4]

Looking into it further, it appears r.in.gdal will set the zone in the
raster header to a negative value if the region is in the southern
hemisphere. But g.setproj will never create a negative zone in the WIND
file (which has the same format as a raster/CELL header), and indicates
that it is in the southern hemisphere by putting south: defined in the
PROJ_INFO file.

pj_get_kv() will accept either south: defined or a negative zone number in
the PROJ_INFO. I suspect if you created the location using r.in.gdal it
would put a negative zone number in the WIND, and d.rast would be
happy.

To summarise: this inconsistency could be fixed either in r.in.gdal or
g.setproj and I'm not sure which would be more appropriate as I don't
understand the significancy of being in the southern hemisphere for the
UTM projection. Maybe somebody could explain this.

Temporary workaround: make sure the zone in the cellhd and WIND are the
same---I'm not sure if they're actually used for anything these days
anyway.

Paul