importing raster maps

[Greg Koerper]

> There are a couple of raster maps I want to import into GRASS 4.1.3. These
> maps are referred to a Gauss-Krueger Projection (central meridian 9.0 degrees
> east, speroid=bessel) with equidistant spacing in N-S and W-E directions in
> this projection.
> As far as I could get out of the GRASS-manuals, importing ASCII-data using
> r.in.ascii or r.in.ll uses an equidistant spacing of lat-lon coordinates.
> Although I dont't know exactly how to arrange this, it should be possible to
> convert the GK coordinates of each single raster cell or it's boundaries into
> lat-lon coordinates with PROJ. But then, the geographic locations of the
> cells should be changed significantly when importing into GRASS.
> Right now, I'm stucked on this problem. I wonder if somebody can give me some
> hints in importing the data into GRASS.
> 
> Thanks in advance
> Ralf Kunkel
> 

After transformation with proj, use the s.menu interactive facility, or the
s.to.rast executable (src is in src.contrib/OTHER), to build a raster from the
site coordinates.  The site data will be placed in the appropriate cells.
You will then need to fill in any "holes" left in the raster using
r.neighbors (and subsequent r.mapcalc to patch the holes) or some interpolation
utility, like r.surf.idw.

greg

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Greg Koerper                            Internet: greg at heart.cor.epa.gov
ManTech Environmental Technology, Inc.  
US EPA Environmental Research Lab	voice:	(503) 754-4490
200 SW 35th St., JSB                    fax:    (503) 754-4338
Corvallis, OR   97333     

"Too much of our discussion here, I am afraid, has dealt with proposals for
man's exercising control over nature without reference to the kind of control
he must exercise over himself." -- L. Mumford
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