[GRASS-user] Output projection questions

Santiago Timón stimonmail at gmail.com
Mon Apr 29 04:06:01 PDT 2013

Hi everyone,

I am going to write a long post, just to put in context and try to explain
why I am having these issues.

I am still making my first steps with 52North WPS and its GRASS backend.

I have tried the process r.loss and I receive the tiff resulting file fine,
but I just realized it comes projected in EPSG:404000 (2D wildcard
coordinate reference system in meters), or at least is how Geoserver
interpretes it. If I try to request the layer with any other SRS openlayers
does not show it, so I assume it is because of 2D wildcard projection.
My input raster map is projected in EPSG:25830 (30N UTM) so I assumed the
output raster would be in the same coordinate system.
I referred to GRASS documentation and read that GRASS manage projections in
a using LOCATIONS.

The tutorial [1] indicates to use the demo location under GRASS
installation folder "GRASS_INSTALL_PATH/demolocation" the
GRASS_INSTALL_PATH/demolocation/PERMANENT/PROJ_INFO file contains:

name: Lat/Lon
datum: wgs84
towgs84: 0.000,0.000,0.000
proj: ll
ellps: wgs84

I assume this is the default projection GRASS is using when invoked from
WPS processes.

I tried to use another location using EPSG:25830 but still the resulting
geotiff is in EPSG:404000.

To do this first I have used GRASS GUI to use the location wizard to add a
new location with EPSG:25830 as default. The PROJ_INFO file under
~/grassdata/30N/PERMANENT/ looks like

name: Universal Transverse Mercator
proj: utm
datum: etrs89
ellps: grs80
zone: 30
towgs84: 0,0,0,0,0,0,0
no_defs: defined

Also added copied .grassrc70 to 30N folder and changed it contents to

GISDBASE: /home/administrador/grassdata
GUI: text

Maybe I am not understanding how to work with projections...
I really hope anyone can help me out with this because I need r.los
algorithm to be invoked from WPS.


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