[GRASSLIST:2690] Re: stitching geotiffs
Richard Greenwood
rich at greenwoodmap.com
Thu Feb 19 18:01:23 EST 2004
Martin du Saire wrote:
> Hi,
>
> I am a newbie to GRASS (XT, Cygwin/XFree86; GRASS5.0) and GIS trying to
> stitch together a set of NLCD Geo-Tiff (USGS Landsat-5, etc.) data
> files for a set of contiguous states in the US. I finally figured out
> how to import them using r.in.gdal -o. (If there is some inherent
> problem with overriding the projection checking, please let me know.)
If you are importing an image in UTM Zone X into a location defined as
UTM Zone X, then you are doing the correct thing by using -o. (You
should not use -o to import Zone X into a location of Zone Y). You may
also want to use -e, which extends the location if needed.
> For starters, how do I go about importing the individual files with
> their corresponding UTM zone designations into the same project?
Do I understand correctly that you have images in Zone X, Y Z ... and
want to have them all in a single projection? If I understand correctly,
then you need to use r.proj to reproject from the individual zones into
the single target projection. But maybe I do not understand you goal.
> Assuming I can figure that out, do I use r.mask to remove the background
> from each of these maps?
You probably do not need to mask. I am guessing that the background is
NULLs?
--
Richard Greenwood
www.greenwoodmap.com
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