[R-sig-Geo] focalFilter problem raster package

[Nick Hamm]

Dear Robert

I hope the following example is clear.  you should be able to cut and paste...

Nick

library(raster)

tmp <- c(55, 56, 54, 58, 65, 75, 82, 77, 74, 74, 69, 61, 62, 71, 73,
63, 62, 63, 64, 59, 85, 88, 95, 106, 110, 99, 89, 82, 79, 84, 97, 79,
55, 55, 56, 60, 91, 95, 86, 98, 115, 105, 110, 107, 101, 89, 85, 68,
55, 54, 53, 61, 82, 102, 88, 93, 96, 94, 110, 114, 109, 103, 92, 68,
59, 58, 60, 64, 88, 99, 82, 81, 71, 80, 89, 89, 89, 102, 104, 75, 63,
57, 58, 58, 77, 92, 82, 71, 59, 90, 105, 92, 79, 98, 110, 83, 62, 55,
56, 56, 80, 90, 99, 88, 64, 91, 112, 94, 76, 91, 100, 85, 62, 59, 55,
61, 99, 97, 93, 80, 65, 87, 107, 80, 59, 60, 67, 66, 65, 62, 68, 72,
102, 94, 90, 83, 74, 81, 96, 69, 52, 50, 51, 54, 62, 62, 86, 85, 55,
59, 64, 72, 75, 70, 70, 62, 66, 61, 55, 57, 52, 59, 61, 56, 41, 40,
43, 44, 46, 48, 50, 52, 68, 69, 60, 61, 42, 43, 44, 43, 42, 41, 42,
44, 43, 43, 44, 47, 58, 59, 55, 61, 44, 41, 39, 42, 44, 43, 42, 42,
42, 43, 43, 49, 56, 53, 53, 61, 43, 42, 40, 42, 42, 42, 41, 42, 42,
43, 42, 53, 66, 61, 51, 62, 40, 42, 41, 40, 43, 49, 46, 42, 42, 43,
43, 49, 59, 62, 53, 62, 40, 41, 42, 43, 49, 54, 47, 44, 42, 44, 43,
46, 52, 56, 56, 61)

tmp <- matrix(tmp, ncol=16, nrow=16, byrow=T)
p267 <- tmp
rm(tmp)
p267.r <- raster(p267)

w.ij.2 <- c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)

w.ij.2 <- matrix(w.ij.2, 15, 15)

sum(w.ij.2 * p267[-16,-16])
sum(w.ij.2 * p267[-16,-1])
sum(w.ij.2 * p267[-1,-16]) #Cell 136 in the raster
sum(w.ij.2 * p267[-1,-1]) #Cell 137 in the raster

tmp <- focalFilter(p267.r, filter=w.ij.2, fun=sum)

tmp[136]
tmp[137]




On 5 April 2011 07:23, Robert Hijmans <r.hijmans at gmail.com> wrote:
>
>> I am experiencing a strange problem when using the focalFilter
>> function in the raster package.
>
> Nick,
> Could you provide a self-contained example that does not require downloading
> files? Given your description that should not be very hard.
> Robert
>
> --
> View this message in context: http://r-sig-geo.2731867.n2.nabble.com/focalFilter-problem-raster-package-tp6235925p6241121.html
> Sent from the R-sig-geo mailing list archive at Nabble.com.
>
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