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

Paul Kelly paul-grass at stjohnspoint.co.uk
Tue Oct 7 06:48:28 EDT 2003

On Thu, 25 Sep 2003, Paul Kelly wrote:

> 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.

And looking even further, it appears that some old coorcnv library
functions add a large false northing if the zone in the WIND file is
negative, so it appears this was the original intention of the GRASS
authors and the authors of g.setproj (which was not developed at CERL if I
remember correctly) just got this bit wrong.

So I have changed g.setproj to put a negative zone number in the
DEFAULT_WIND if the answer is yes to the southern hemisphere question. But
probably in the future this issue is bound to cause a few more problems to
people because of the inconsistencies we have observed between different
GRASS modules.


More information about the grass-dev mailing list