Hi Martin, r.pi.nlm sounds really suitable for such tasks, I should really have a look into it. As I recognized you as one of the maintainers, do you think it'll be available also as an add-on for GRASS7?
cheers, Johannes On Fri, Jan 10, 2014 at 11:59 AM, M Wegmann <[email protected]> wrote: > Hi Johannes, > > you might want to look into the r.pi. suit[1]. You will find a command > called > r.pi.nlm which generates random landscapes based on some settings (e.g. % > coverage). > > cheers, Martin > > > http://svn.osgeo.org/grass/grass-addons/grass6/raster/r.pi/ > > > On Friday, January 10, 2014 09:57:12 AM Robert Nuske wrote: > > Hi Johannes > > > > another path might be to use the excellent tools of the R package > spatstat > > to simulate various cluster processes. Those generated point patterns > could > > then be translated to rasters. > > > > Functions for random point processes exhibiting clustering in spatstat > are > > e.g. rThomas, rGaussPoisson, rMatClust, rcell (retrieved from the help > page > > of rpoispp). > > > > The simulated point density will of course not always have exactly the > > requested density. > > > > > > cheers > > robert > > > > Am Freitag, 10. Januar 2014, 08:17:50 schrieb Johannes Radinger: > > > Hi Markus, > > > > > > so far as I understood r.random.cell creates spatially most > disaggregated > > > cells (based on the distance parameter). So instead of clumping them > this > > > module does the opposite. > > > > > > However, I am just trying another solution which might be promising: > With > > > r.random.surface > > > it is possible to generate a spatially dependent surface (like a > landscape > > > with mountains and valleys). Then I can use r.quantile to get the > > > lowest/highest e.g 20% of all values and consequently I can use > r.mapcalc > > > to reclassify all values smaller than the threshold value I yielded > from > > > r.quantile. First trials yielded good results although the 20% > threshold > > > did not exactly translate into 20% of all cells. I've to investigate a > > > little bit more into that. Any other suggestions? > > > > > > Best regards, > > > Johannes > > > > > > On Fri, Jan 10, 2014 at 12:43 AM, Markus Neteler <[email protected]> > wrote: > > > > On Thu, Jan 9, 2014 at 4:09 PM, Johannes Radinger > > > > > > > > <[email protected]> wrote: > > > > > Hi, > > > > > > > > > > just two short question concerning the creation of random cells. > > > > > So far I used r.random to create e.g. a map with 20% cells (of my > > > > > input > > > > > raster). > > > > > I'd like to know: > > > > > 1) Is there a way to create randomly spatially clumped rasters > cells > > > > > so > > > > > > > > that > > > > > > > > > the cells > > > > > look aggregated like patches, while still setting the e.g. 20% > limit? > > > > > > > > Maybe > > > > > > > > > with a factor of spatial autocorrelation!? Maybe somebody has an > > > > > example > > > > > 2) Is there a way to set a fixed seed to make reproducible results > > > > > with > > > > > r.random and similar modules? > > > > > > > > While likely not a solution for you but take a look at > > > > http://grass.osgeo.org/grass70/manuals/r.random.cells.html > > > > > > > > Markus > > > > _______________________________________________ > > grass-user mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/grass-user > >
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