Re: [GRASS-user] cutting issue (again): r.mapcalc vs. r.resample
Did you do: g.copy rast=boundary_raster,MASK or alternatively: r.mask input=boundary_raster -o (-o for overwrite) ? Tim Michelsen schrieb: Hello, I while ago I asked how to cut a small map from a larger one using the region settings as boundary for the small map: http://n2.nabble.com/r-mapcalc-changes-color-table-td4072836.html#a4072836 I tried this again: Approach 1: r.mapcalc r.mapcalc cut=if(boundary_raster, large_map, null()) Approach 2: r.resample r.resample input=large_map output=cut I notice the that using Approach 2, the areas that was outside the set region is white. The underlayung rasters are not visible (or only if I set the opacity of cut to a low value). If I use Approach 1 with r.mapcalc, the areas outside the region are really NULL() (=transparent) and underlaying larger rasters are visible. Only that the result cut from r.mapcalc has a new colortable. Am I doing something wrong? Why is the no such command r.cut? Thanks in advance for your help, Timmie ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] cutting issue (again): r.mapcalc vs. r.resample
And more: -%-- ...The category values in the new raster output map layer will be the same as those in the original, except that the resolution and extent of the new raster output map layer will match those of the current geographic region settings (see g.region) -%-- Achim Tim Michelsen schrieb: Hello, I while ago I asked how to cut a small map from a larger one using the region settings as boundary for the small map: http://n2.nabble.com/r-mapcalc-changes-color-table-td4072836.html#a4072836 I tried this again: Approach 1: r.mapcalc r.mapcalc cut=if(boundary_raster, large_map, null()) Approach 2: r.resample r.resample input=large_map output=cut I notice the that using Approach 2, the areas that was outside the set region is white. The underlayung rasters are not visible (or only if I set the opacity of cut to a low value). If I use Approach 1 with r.mapcalc, the areas outside the region are really NULL() (=transparent) and underlaying larger rasters are visible. Only that the result cut from r.mapcalc has a new colortable. Am I doing something wrong? Why is the no such command r.cut? Thanks in advance for your help, Timmie ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] cutting issue (again): r.mapcalc vs. r.resample
On Mon, 25 Jan 2010, Tim Michelsen wrote: I while ago I asked how to cut a small map from a larger one using the region settings as boundary for the small map: http://n2.nabble.com/r-mapcalc-changes-color-table-td4072836.html#a4072836 I tried this again: Approach 1: r.mapcalc Approach 2: r.resample Am I doing something wrong? Tim, Looks like it. I asked for guidance on doing just what you need to do: cut out the project area from a larger DEM. The approach that worked for me was described by Helmut Kudrnovsky: 1) zoom to your area of interest of your larger region. 2) v.in.region e.g. v.in.region output=testarea, so the extent of your area of interest is defined by the vector testarea 3) g.region vect=testarea, by this the region is set to your area of interest for analysis. This region defines the geographic area in which all GRASS displays and raster analyses will be done. Works like a charm. Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] cutting issue (again): r.mapcalc vs. r.resample
On Mon, 25 Jan 2010, Hamish wrote: the v.in.region and g.region vect= steps are redundant, but make sure when you zoom you update the computational region, not just the display one in the GUI (d.zoom + d.mon does this automatically) Hamish, Good to know. Thanks. I'm a CLI person so I use the GUI only to start GRASS because I've hated that crude, mid-1980s ncurses starting interface for years. Otherwise I much prefer to work in a virtual console at the command line. Much more comfortable for me. However, I will concede that I've found the LaTeX GUI front-end, LyX, to be much quicker and more productive than writing LaTeX in emacs. So I'm not totally averse to using the pointy-thingie when it's demonstrably more productive. :-) Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
