On Friday, May 24, 2013, Glynn Clements wrote: > > Rainer M. Krug wrote: > > > >> Hmm - sounds interesting, but also for other purposes. But as the > result > > >> will be a raster map, I don't think this approach is usable here > (unless > > >> I can feed the numbers back into a raster map, i.e. the inverse of > > >> r.stats -c) > > > > > > r.cross + r.reclass ? > > > > There is one aspect in r.cross which makes this approach quite > > difficult to implement: the value of the result map layer can not easily > > be traced back to the values of the two input layers: > > If you only have a small number of classes, you can just create the > cross-product manually, e.g.: > > r.mapcalc 'result = ageClass * 10 + dc'
Yes - This is effectively what I am doing now. > > So a category of 15 would be ageClass=1, dc=5. > > r.cross is more useful when the total number of pairs which actually > occur is much fewer than the product of the numbers of categories, as > it only creates a category for each combination which actually occurs, > not for each potential combination. True. The problem I have with r.cross is that I have to manually decode afterwords what combination the value refers to. I could use a she'll script to translate the category values, but this sounds a little tedious, especially as the format is not that easily parsable. Cheers, Rainer > > -- > Glynn Clements <[email protected] <javascript:;>> > -- NEW GERMAN FAX NUMBER!!! Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys. (Germany) Centre of Excellence for Invasion Biology Natural Sciences Building Office Suite 2039 Stellenbosch University Main Campus, Merriman Avenue Stellenbosch South Africa Cell: +27 - (0)83 9479 042 Fax: +27 - (0)86 516 2782 Fax: +49 - (0)321 2125 2244 email: [email protected] Skype: RMkrug Google: [email protected]
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