Thanks Paulo and Thomas, perfect the r.surf.random <https://grass.osgeo.org/grass70/manuals/r.surf.random.html> does what i want!! I know how to implement the code! Thanks!! p.s. better to put the r.surf.random <https://grass.osgeo.org/grass70/manuals/r.surf.random.html> link at the bottom of r.random.surface <https://grass.osgeo.org/grass70/manuals/r.random.surface.html>
On 16 February 2016 at 03:47, Paulo van Breugel <p.vanbreu...@gmail.com> wrote: > > > On 16-02-16 05:04, Thomas Adams wrote: > > Giuseppe, > > Unless I have misunderstood, in GRASS use r.mapcalc... > > First set you region for your area of interest, for example: > > g.region -dp e=2614612.5 w=1423987.5 n=-4624387.5 s=-5862637.5 > > Then: > r.mapcalc expression="outputMap=25.4" > > where 25.4 is your value of interest, and finally: > > r.out.gdal input=outputMap output=outputFileName format=GTiff > > Best, > Tom > > On Mon, Feb 15, 2016 at 9:33 PM, Giuseppe Amatulli < > <giuseppe.amatu...@gmail.com>giuseppe.amatu...@gmail.com> wrote: > >> Hi, >> I would like to create an uniform random raster, similar to what i would >> obtain in R with the following code >> >> raster=raster(matrix(runif(54210, max=50, min=-50, 139,390) , ...........) >> writeRaster(raster,filename=random.tif",formats=GTiff,overwrite=TRUE) >> >> I read the explanation of >> https://grass.osgeo.org/grass7/manuals/r.random.surface.html >> and also r.mapcalc - random (a,b) >> but I'm not sure if one of them produce the same concept/result. >> > > That function creates random surface(s) with spatial dependence (there is > a small typo in the link, it should be grass70). What you want, I think, is > the r.surf.random function ( > <https://grass.osgeo.org/grass70/manuals/r.surf.random.html> > https://grass.osgeo.org/grass70/manuals/r.surf.random.html). The > r.mapcalc - random(a,b) should also do what you want, it also gives a > uniform distribution. > > p.s. some of the brackets in your R code above are off, it should probably > be something like raster=raster(matrix(runif(54210, max=50, min=-50), > 139,390) , ...........). Like Thomas wrote, in GRASS you first need to > define your region and set your resolution (check out g.region for all > settings, including the option to set number of rows and columns). Than you > can run r.surf.random or r.mapcalc to generate your new random surface > layer. > > >> Any input? or better explanation >> >> Thanks >> Best >> Giuseppe >> >> -- >> Giuseppe Amatulli, Ph.D. >> >> Department of Ecology and Evolutionary Biology, Yale University. >> Jetz Lab, OML Room 405 >> >> P.O. Box 208106 >> 165 PROSPECT ST >> New Haven, CT 06520-8106 >> Teaching: spatial-ecology.net >> Work: http://sbsc.yale.edu/giuseppe-amatulli >> >> _______________________________________________ >> grass-user mailing list >> grass-user@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/grass-user >> > > > > -- > Thomas E Adams, III > 2330 Jack Warner PKWY, #334 > Tuscaloosa, AL 35401 > > 1 (513) 739-9512 (cell) > > > > _______________________________________________ > grass-user mailing > listgrass-user@lists.osgeo.orghttp://lists.osgeo.org/mailman/listinfo/grass-user > > > -- Giuseppe Amatulli, Ph.D. Department of Ecology and Evolutionary Biology, Yale University. Jetz Lab, OML Room 405 P.O. Box 208106 165 PROSPECT ST New Haven, CT 06520-8106 Teaching: spatial-ecology.net Work: http://sbsc.yale.edu/giuseppe-amatulli <http://www.spatial-ecology.net>
_______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user