Re: Cropping maps
Markus Metz <[email protected]>
| Newsgroups | gmane.comp.gis.grass.user |
|---|---|
| Message-ID | <CAG+h=FGmV6p7wLZJ1oe3dwsnXcWZYKANj0AKAWKj5U=mF2FZXw@mail.gmail.com> |
On Fri, Dec 1, 2017 at 4:26 PM, Vaclav Petras <[email protected]> wrote: > > For cropping, see also a new addon module called r.clip which clips according the computational region while respecting mask and the *original* raster resolution: > > https://grass.osgeo.org/grass72/manuals/addons/r.clip.html > > Testing and feedback welcome. About https://trac.osgeo.org/grass/browser/grass-addons/grass7/raster/r.clip/r.clip.py#L42 g.region align=original is sufficient. You don't need to specify nsres or ewres when aligning to a raster map because nsres and ewres of the raster map are used anyway for alignment. Markus M > > Vaclav > > On Tue, Sep 26, 2017 at 10:35 AM, Moritz Lennert < [email protected]> wrote: >> >> On 26/09/17 16:17, Moritz Lennert wrote: >>> >>> On 26/09/17 15:57, Marco Alicera wrote: >>>> >>>> Dear list, >>>> I am trying to crop a raster map into a smaller area, but I am failing. >>>> >>>> This wiki page link <https://grasswiki.osgeo.org/wiki/Cropping_maps> is >>>> quite clear: >>>> "Make boundary into mask using r.mask >>>> <https://grass.osgeo.org/grass72/manuals/r.mask.html> then copy raster >>>> source to new map (g.copy >>>> <https://grass.osgeo.org/grass72/manuals/g.copy.html>). All cells >>>> outside of the mask will be omitted from the new copy." >>>> >>>> r.mask vector=myarea >>>> g.copy --overwrite raster=OldRasterWithBigArea,NewRasterWithSmallArea >>>> r.mask -r >>>> >>>> I expected all cell outside were not going to be omitted, but replaced >>>> by NULL. >>> >>> >>> I'm not sure I understand your last sentence, but AFAIK, the wiki info >>> is wrong. g.copy works directly on the files and ignores mask and region >>> settings. In your example, OldRasterWithBigArea and >>> NewRasterWithSmallArea should be strictly identical. >>> >>> You need to use r.mapcalc "new = old" while the mask is set to get a >>> raster with everything outside the mask set to NULL. >> >> >> I've rewritten the wiki page to try to make things clearer. >> >> >> Moritz >> _______________________________________________ >> grass-user mailing list >> [email protected] >> https://lists.osgeo.org/mailman/listinfo/grass-user > > > > _______________________________________________ > grass-user mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user