[R-sig-Geo] Fwd: clump of binary pixels on raster package

Dylan Beaudette dylan.beaudette at gmail.com
Mon May 11 00:42:56 CEST 2009


Hi,

What version of GRASS are you using? Have you asked on the GRASS list
regarding the slow r.clump [-ing] ?

Cheers,

Dylan

On Sun, May 10, 2009 at 2:30 PM, milton ruser <milton.ruser at gmail.com> wrote:
> Dear all,
>
> sorry for this double-posting, I know it is not a good idea,
> but may be this list is more appropriated for this issue.
>
> Thanks a lot
>
> milton
>
> ---------- Forwarded message ----------
> From: milton ruser <milton.ruser at gmail.com>
> Date: Sat, May 9, 2009 at 5:59 PM
> Subject: clump of binary pixels on raster
> To: "r-help at r-project.org" <r-help at r-project.org>
>
>
> Dear all,
>
> I have a set od 30,000 binary landscapes, which represent habitat and
> non-habitat cover.
> I need to generate images that identify those neighbour (rule 8) pixels as
> one patch ID,
> and a different patch ID for each clump of pixels. I coded it using
> labcon(adehabitat),
> but as some of my landscapes have so many patches, labcon not finish and
> entry in
> a eternal looping. By other side, I coded another solution using R & grass
> (r.clump),
> but the solution is so slow, and as I need to run it a lot of time, I will
> need about 3 weeks
> to finish... I was thinking if raster package could do the job fastly than
> R-grass.
> Below you can find a simulation of what I need. On the second image, each
> color
> have different values.
>
> MyMatrix<-matrix(rep(0,100), ncol=10)
> MyMatrix[2:4,3:6]<-1
> MyMatrix[7:8,1:3]<-1
> MyMatrix[8,7:8]<-1
> MyMatrix[8,7:8]<-1
> MyMatrix[6:7,8:9]<-1
> x11(800,400)
> par(mfrow=c(1,2))
> image(MyMatrix)
>
> MyClusters<-matrix(rep(0,100), ncol=10)
> MyClusters[2:4,3:6]<-1
> MyClusters[7:8,1:3]<-2
> MyClusters[8,7:8]<-3
> MyClusters[8,7:8]<-4
> MyClusters[6:7,8:9]<-4
> image(MyClusters, col=c("transparent", 1,3,4,5))
>
> Regards a lot,
>
> milton
> brazil=toronto.
>
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>
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