[GRASS-user] borken links in web site
Hi all. In the web page: http://grass.osgeo.org/gdp/tutorials.php there are several broken links, e.g. http://home.wlu.edu/~dharbor/gisrs/index.html http://www.geo.unipr.it/~gis/ All the best. -- Paolo Cavallini: http://www.faunalia.it/pc ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: r.mapcalc changes color table
Tim Michelsen wrote: > >>> 6) use r.mapcalc to cut: r.mapcalc "cut=if(boundary_raster, large_map, > >>> null())" > >> > >> Replace step 6 with: > >> > >> g.copy rast=boundary_raster,MASK > >> r.resample input=large_map output=cut > >> g.remove rast=MASK > >> > > > > Can someone perhaps explain why steps 4 and 5 are necessary? > > (My understanding is that r.mapcalc anyway observes the region settings) > > > > > > Couldn't step 6 be simplified to: r.mapcalc cut = large_map > > ? > I don't know. That was the approach I have always seen and been told. > > The question is: > when do I use r.resample and when do I use r.mapcalc to cut a smaller > portion from a large raster map? "r.mapcalc 'cut = large_map'" is equivalent to "r.resample in=large_map out=cut". > from the man page: > The method by which resampling is conducted is "nearest neighbor" (see > r.neighbors). The resulting raster map layer will have the same > resolution as the resolution of the current geographic region (set using > g.region). > > I actually do not want to extract by sampling than rather copy a smaller > area from the large map. If the current region has the same resolution as the input map, then there will be a 1:1 correspondence between input cells and output cells. All raster modules perform nearest-neighbour resampling, as the underlying GRASS libraries automatically resample input maps to the current region. The modules which perform other types of resampling (r.resamp.interp, r.resamp.stats, r.resamp.rst) set the current region resolution and alignment to match the input map, making the nearest-neighbour resampling step a no-op. -- Glynn Clements ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Re: r.mapcalc changes color table
Hermann Peifer wrote: > >> I have a large georeferenced digital map. > >> > >> I successfully imported it into GRASS. > >> > >> Now I would like to "cut" only a small rectangle -- my investigation > >> area -- out of this large map. > >> > >> I used the following approach: > >> > >> 1) import the TIFF > >> 2) select the part of interest in the GRASS monitor > >> 3) set the zoomed area as region (monitor tools) > >> 4) create a boundary vector: v.in.region > >> 5) convert boundary raster to a raster v.to.rast > >> 6) use r.mapcalc to cut: r.mapcalc "cut=if(boundary_raster, large_map, > >> null())" > > > > Replace step 6 with: > > > > g.copy rast=boundary_raster,MASK > > r.resample input=large_map output=cut > > g.remove rast=MASK > > > > Can someone perhaps explain why steps 4 and 5 are necessary? > (My understanding is that r.mapcalc anyway observes the region settings) I wasn't paying attention. For a rectangular area, you can just change the region then make a copy with r.resample or r.mapcalc. I was assuming an arbitrary (not necessarily rectangular) region. For a rectangular region, steps 3 through 6 can be replaced with a single call to r.resample. > Couldn't step 6 be simplified to: r.mapcalc cut = large_map > ? Which is equivalent to "r.resample in=large_map out=cut". Using r.resample is probably more convenient from the GUI, as you can select the input from a list. -- Glynn Clements ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Importing Converted Points File
I converted a points file from lon/lat geographic coordinates to lcc using cs2cs. The command line used was: cs2cs +proj=latlong +datum=NAD83 +to +proj=lcc +datum=NAD83 +ellps=GRS80 \ +lat_1=43.0 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=1312336 +y_0=0 \ +nadgrids=WO < v.in.ascii input=keypoints/sites_lcc.txt output=sites format=point x=0 y=1 ERROR: Column numbers must not be negative Do I just change the longitude values to positive? Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Creating Points Map
On Fri, 27 Nov 2009, Rich Shepard wrote: I'm not getting results because of a syntax error. Here's the script: cs2cs +proj=latlong +datum=NAD83 +to +proj=lcc +datum=NAD83 +ellps=GRS80 +lat_1=43.0 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=1312336 +y_0=0 +nadgrids=WO 122d30'32.43" 45d19'19.49" 122d30'17.92" 45d18'52.45" 122d29'34.08" 45d18'47.16" EOF Got it. Have to enter it on the command line rather than running it as a script. Thanks, Daniel, Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Creating Points Map
On Fri, 27 Nov 2009, Rich Shepard wrote: Here's the script: Lost something when cutting and pasting: cs2cs +proj=latlong +datum=NAD83 +to +proj=lcc +datum=NAD83 +ellps=GRS80 +lat_1=43.0 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=1312336 +y_0=0 +nadgrids=WO
Re: [GRASS-user] Creating Points Map
On Fri, 27 Nov 2009, Daniel Victoria wrote: You forgot the < Nope. Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Creating Points Map
You forgot the < wrote: > On Thu, 26 Nov 2009, Daniel Victoria wrote: > >> If it's just 3 points, why not reproject them first and them import into >> Grass inside your final location? > > Daniel, > > Good idea. > >> Take a look at the proj comand and the cs2cs. It will project your lat >> long points. The cs2cs will allow for datun shifts > > I'm not getting results because of a syntax error. Here's the script: > > cs2cs +proj=latlong +datum=NAD83 +to +proj=lcc +datum=NAD83 +ellps=GRS80 > +lat_1=43.0 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=1312336 +y_0=0 > +nadgrids=WO 122d30'32.43" 45d19'19.49" > 122d30'17.92" 45d18'52.45" > 122d29'34.08" 45d18'47.16" > EOF > > When I run the script nothing is returned; after a while I kill the > process with ^C. What have I missed here? > > Thanks, > > Rich > ___ > 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] Creating Points Map
On Thu, 26 Nov 2009, Daniel Victoria wrote: If it's just 3 points, why not reproject them first and them import into Grass inside your final location? Daniel, Good idea. Take a look at the proj comand and the cs2cs. It will project your lat long points. The cs2cs will allow for datun shifts I'm not getting results because of a syntax error. Here's the script: cs2cs +proj=latlong +datum=NAD83 +to +proj=lcc +datum=NAD83 +ellps=GRS80 +lat_1=43.0 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=1312336 +y_0=0 +nadgrids=WO 122d30'32.43" 45d19'19.49" 122d30'17.92" 45d18'52.45" 122d29'34.08" 45d18'47.16" EOF When I run the script nothing is returned; after a while I kill the process with ^C. What have I missed here? Thanks, Rich ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.to.rast Segmentation fault
Hi all, I just installed the grass distribution with version 6.4.0 RC5 on a linux box (Ubuntu 9.10) downloaded from the website. (not cvs) I'm trying to work with the "v.to.ras" module as a CLI and I'm unsing this command to get some help message: /usr/local/grass-6.4.0RC5/bin/v.to.rast help and... the result is a wonderful Segmentation fault. Does someone has any idea? Thanks. -- GP. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Defining location/mapset
Hello people I'm planning to use GRASS but I have one question about location/mapset organization. I'm going to do some classification and image processing for a certain region of Spain at 3 different levels: local, regional and national. This different scales have different scale definition with higher scale definition for local and lower for national (1:100). I will use different satellite images for different scales but some vectorial (e.g. roads) will be used for all three scales. National scale includes all country, regional only a certain region and local (a specific and very small area). According to GRASS database and common structure I will store my data at a GISDBASE. Within this directory, GRASS GIS data are organized by projects. Since its location is defined by its coordinate system, map projection and geographic boundaries my question is: Should I have a different location for each scale? I would say so, right? If that is the case, I would define mapsets as different data sources or produced maps. Thanks all, Luis Lisboa ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] help(isodistances map)
hi all, how to generate a map of apathetic isodistances several nodes, but having a special attribute such as cost per node, but as a surface thanks for any response Estudiante de ultimo semestre de ING. TOPOGRAFICA ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] help(shortest path matrix values)
hi all, I am struggling to find the shortest path from all points of a network, and that these distances are printed in a matrix in the same way that the command "v.distance" as with the command " d.path "couples only one set, I need to save and get all the shortest distances from one point to all the rest of the network into a network matrix. thanks for any response Estudiante de ultimo semestre de ING. TOPOGRAFICA ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: r.mapcalc changes color table
First, thanks to all who responded. I will try and apply that later. >>> 6) use r.mapcalc to cut: r.mapcalc "cut=if(boundary_raster, large_map, >>> null())" >> >> Replace step 6 with: >> >> g.copy rast=boundary_raster,MASK >> r.resample input=large_map output=cut >> g.remove rast=MASK >> > > Can someone perhaps explain why steps 4 and 5 are necessary? > (My understanding is that r.mapcalc anyway observes the region settings) > > > Couldn't step 6 be simplified to: r.mapcalc cut = large_map > ? I don't know. That was the approach I have always seen and been told. The question is: when do I use r.resample and when do I use r.mapcalc to cut a smaller portion from a large raster map? from the man page: The method by which resampling is conducted is "nearest neighbor" (see r.neighbors). The resulting raster map layer will have the same resolution as the resolution of the current geographic region (set using g.region). I actually do not want to extract by sampling than rather copy a smaller area from the large map. It would be nice to receive a best practice confirmation on this by a GRASS power user. Is there a "best practice page" in the wiki where this could be added? Thanks in advance, Timmie ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] r.walk [Fwd: Re: [GRASS-stats] r.cost]
Original Message Subject: Re: [GRASS-stats] r.cost Date: Thu, 26 Nov 2009 20:15:34 +0100 From: Agustin Lobo Reply-To: agustin.l...@ija.csic.es To: Jarek Jasiewicz CC: agustin.l...@ija.csic.es, GRASS STATS References: <4b0ebcb2.1080...@gmail.com> <4b0ec072.6020...@amu.edu.pl> Yes, thanks, r.walk is the appropriate module. In case there are several starting coordinates, how are the different costs combined? the lowest as in r.cost? Agus Jarek Jasiewicz wrote: Agustin Lobo pisze: Hi! Is there any way to weight the accumulation in r.cost so that going uphill is harder than going downhill? Thanks Agus ___ grass-stats mailing list grass-st...@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-stats seems that r.walk could be the answer J. ___ grass-stats mailing list grass-st...@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-stats ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Re: r.mapcalc changes color table
Glynn Clements wrote: Tim Michelsen wrote: I have a large georeferenced digital map. I successfully imported it into GRASS. Now I would like to "cut" only a small rectangle -- my investigation area -- out of this large map. I used the following approach: 1) import the TIFF 2) select the part of interest in the GRASS monitor 3) set the zoomed area as region (monitor tools) 4) create a boundary vector: v.in.region 5) convert boundary raster to a raster v.to.rast 6) use r.mapcalc to cut: r.mapcalc "cut=if(boundary_raster, large_map, null())" Replace step 6 with: g.copy rast=boundary_raster,MASK r.resample input=large_map output=cut g.remove rast=MASK Can someone perhaps explain why steps 4 and 5 are necessary? (My understanding is that r.mapcalc anyway observes the region settings) Couldn't step 6 be simplified to: r.mapcalc cut = large_map ? Hermann ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
