[AniMov] kernelbb and extent

Anna Skarin Anna.Skarin at slu.se
Fri Jun 8 08:37:54 CEST 2012

Dear All,

I'm struggling with the kernelbb in adehabitatHR. I'm calculating the Brownian Brigdes Home Range (BBHR) for reindeer using GPS-data from a number of reindeers. However when I'm using the kernelbb() I get somewhat different results depending on the number of burst included in the ltraj used in the kernelbb, even though I state the same grid size and extent. So is there a bug here or I'm doing things the wrong way, or thinking the wrong way? The function seems to fit the HR to the extent of the total data and not to the single burst, even though the same extent is defined in the function.

All the best,
Anna Skarin
(Sorry for any double posting)

Here is my script and please download example data from:


ltraj1 <- ltraj4[c(1)]

sig2 <-10
renLiker <- liker(ltraj4, sig2, byburst=TRUE, rangesig1=c(0,20), plotit=F)
renMedian <- median(sapply(renLiker, function(x) x$sig1))

#Here I use the same sig1 in all estimations for comparison
ren1<-kernelbb(ltraj1, sig1=renMedian, sig2, byburst=TRUE, grid=50, extent=0.5)
ren4<-kernelbb(ltraj4, sig1=renMedian, sig2, byburst=TRUE, grid=50, extent=0.5)

#compare this plot with....
plot(ltraj1, spixdf=ren1)

#...this plot! shouldn't they be similar?
spren4 <- estUDm2spixdf(ren4)
plot(ltraj4[c(1)], spixdf=spren4)

#or compare these plots and data...
plot(getverticeshr(ren1, 99), lwd=2)
plot(getverticeshr(ren4$r_RG_08_079, 99),add=TRUE, lwd=2)

ren1vol <-getvolumeUD(ren1)
ren4vol <-getvolumeUD(ren4)

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