[GRASSLIST:6138]

[knut.langeland at nina.no]

Hi
I have a problem trying to project the etopo2 model from a lat/long
location to a location with utm33 projection.
As the illustration shows, the etopo2-model is distorted compaired with
the vector map projected from the same location.
 
The lat/lon location has a wgs84 projection, and the etopomodel was
imported with r.in.bin as described in newsletter no. 1 and g.region
rast=etopo2 was used to fit the region to the rastermap. The vectormap
was imported to the same location with v.in.ogr, and the fit between the
etopo2-raster and the vector is good. The utm33 location was also
created with a wgs datum/projection but with raster resolution of 10000
meters, and the maps where projected with 
r.proj input=etopo2 location=latlong mapset=PERMANENT output=etopo2
method=nearest   and
v.proj input=world location=latlong mapset=PERMANENT output=world

So, my question is; what is happening in the projection prosess of the
etopo-raster that is not happening to the vector?
It's obvious that there will be some distortion the further east/west
from the utm33 zone we move, but why is the raster much more distorted
than the vector?  
 
Thanks in advance! 
 

Knut Langeland
ph-d student
Norwegian Institute for Nature Research -NINA
-division of arctic ecology
 
<mailto:d at nina.no>  

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