No problem I was on my phone so I couldnt test it to see how fast the
various methods were.
I really like Roberts approach because of the elegance and safe memory
approach. There is nothing
more fustrating that doing a 'raster' operation and getting back out of
memory error.

On Thu, Oct 18, 2012 at 6:06 AM, aniruddha ghosh <aniru123@gmail.com> wrote:

> Thank you Etienne and Steven for your suggestions.
>
> I tried the ordinary matrix method as suggested by Etienne. It works
> fine. It was fast and produced excellent results for my original
> raster files with 10 values.
>
> Steven, when I try to incorporate more number of cell values, the
> procedure is getting longer as I have to reclassify multiple times for
> different combinations.
>
> Best regards,
>
>
> On Thu, Oct 18, 2012 at 1:50 AM, steven mosher <moshersteven@gmail.com>
> wrote:
> >
> > reclassify r1 to 1 and 0. reclassify r2 to 0 1 and 2.
> > then multiply the rasters.
> > so r1 becomes 0 for all values ecept 1. r2 is 1 or 2 or 0. and the
> product r3 will be 1 or 2 or 0
> >
> > On Oct 17, 2012 11:55 AM, "aniruddha ghosh" <aniru123@gmail.com> wrote:
> >>
> >> Dear List,
> >> I have two raster layers (r1 and r2) and the cells have values ranging
> 1 to
> >> 10. I want to create a new raster layer from these two with different
> >> conditions like:
> >> 1) if r1==1 and r2==1, then r3 should be 1
> >> 2) if r1==1 and r2==2, then r3 should be 2
> >> else 0 etc
> >>
> >> With the following example:
> >>
> >> m1<-matrix(c(1,1,1,2,2,2,3,3,3),ncol=3,byrow=TRUE)
> >> m2<-matrix(c(1,2,1,1,2,3,2,3,3),ncol=3,byrow=TRUE)
> >> r1<-raster(m1)
> >> r2<-raster(m2)
> >> Here, r1[1,1]=1 and r2[1,1]=1, so for the new raster, [1,1] should be 1,
> >> r1[1,2]=1 and r2[1,2]=2, so for the new raster, [1,2] should be 2,
> >> all other cells which don't satisfy the above criteria should be zero.
> >>
> >> I tried with "calc" in raster package but the attempt was not
> successful.
> >>
> >> Looking forward to your suggestions!
> >>
> >>
> >> Thanks
> >> --
> >> Ani
> >>
> >>         [[alternative HTML version deleted]]
> >>
> >> _______________________________________________
> >> R-sig-Geo mailing list
> >> R-sig-Geo@r-project.org
> >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>
>
>
> --
> Ani
>

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