[AniMov] kernelUD error

Hazel, Julia julia.hazel at jcu.edu.au
Sat Mar 5 06:48:39 CET 2011

Dear all,

Many thanks to those who create and maintain AniMov software! 
After a steep learing curve with adehabitat I'm finding it very useful.
However with kernels for short periods, I sometimes get an error.
It seems this is caused by a set of locations that don't change.

### adehabitatHR_0.1  R 2.12.1 Windows XP
#demo: error with animal at same location during period of interest
X <- rep(699889, 10)
Y <- rep(3161559, 10)
Name <- rep("Brock", 10)
test <- data.frame (Name, X, Y)
coordinates(test) <- c("X", "Y") 
ud <- kernelUD(test)
#Error in points2grid(points, tolerance, round, fuzz.tol) : 
#  cannot determine cell size from constant coordinate 1

#demo: no error after small change in one location
XX <- c(rep(699889, 9), 699890)
YY <- c(rep(3161559, 9), 3161560)
Name <- rep("Brock", 10)
test2 <- data.frame (Name, XX, YY)
coordinates(test2) <- c("XX", "YY") 
ud2 <- kernelUD(test2)

Apologies in advance if this problem arises from newbie misunderstanding. However unchanging locations (over a limited time) are a valid occurrence in my data so I will be very grateful for the solution.

Thanks and best wishes,


Julia Hazel Ph.D.
Adjunct Research Fellow
School of Earth and Environmental Sciences
James Cook University, Townsville
QLD 4811
Phone: 0407 431 382 (international +61 407 431 382)
Email: Julia.Hazel at jcu.edu.au

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