[GRASS5] [bug #1492] (grass) r.in.gdal/GRASS/GDAL: coordinates confusion on southern hemisphere (UTM)

Request Tracker grass-bugs at intevation.de
Fri Dec 20 12:31:39 EST 2002


this bug's URL: http://intevation.de/rt/webrt?serial_num=1492
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Subject: r.in.gdal/GRASS/GDAL: coordinates confusion on southern hemisphere (UTM)

grass binary for platform: Compiled from Sources

Hi,

when importing a LANDSAT-TM5 into GRASS
Botswana, UTM Zone 35
with r.in.gdal,I get a coordinates confusion.
A sample dataset is here:
ftp://ftp.glcf.umiacs.umd.edu/glcf/Landsat/WRS2/p173/r072/p173r72_5t890625.TM-EarthSat-Orthorectified/

(get the 1st channel, Geotiff).

After importing the TM1 channel, the cell header contains:
proj:       1
zone:       35
north:      -1818499.5
south:      -2018512.5
east:       499120.5
west:       269040
cols:       8073
rows:       7018
e-w resol:  28.5
n-s resol:  28.5
format:     0
compressed: 1

But the region definition in "GRASS speak" is for a southern hemisphere
area:
g.region -pd
projection: 1 (UTM)
zone:       -35
datum:      ** unknown (default: WGS84) **
ellipsoid:  wgs84
north:      8230695
south:      7629900
west:       3600
east:       525060
nsres:      15
ewres:      15
rows:       40053
cols:       34764

Note (the boundary coordinates are not fully overlapping):
 - negative zone (GRASS) vs positive zone (GDAL)
 - positive N/S coordinates (GRASS) vs negative N/S coordinates (GDAL)

Do we have to fix that in GDAL or in r.in.gdal or is the convention
in GRASS for southern hemisphere bad? If the latter, how to solve the
problem (I have several data sets...).

Thanks,

 Markus


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