[AniMov] LoCoH isopleths intervals... to e.g. 5%?

Clément Calenge clement.calenge at oncfs.gouv.fr
Fri Feb 12 09:46:20 CET 2010

Hello Henrik,

Henrik Lundqvist wrote:
> I got a question regarding the k-NNCH or LoCoH funktion in Adehabitat 
> for calculating homeranges.
> The default setting regaring the isopleths are 10% steps as follows: 
> c(100,90,80,70,60,50,40,30,20,10)
> Is there a parameter I can change to achieve 5% steps (or other 
> configuration)? I can't find it in the arguments of the function. 
> There seems to be a possibility to set more intervals in the 
> ArcGIS-plugin at: 
> http://nature.berkeley.edu/~alyons/locoh/arcgis9/index.html 
> <http://nature.berkeley.edu/%7Ealyons/locoh/arcgis9/index.html>
> I guess I have to engage with the code of NNCH.R, but when I try (the 
> R-guru that I'm not) I get errors.
> Couldn't it be coded as an argument of the function? Would be neat...

Actually, the function NNCH returns an object of class "NNCH" containing 
all possible isopleths that can be built with a given dataset. Then, 
other functions are used to "extract" given isopleths. For example, if 
you want to compute the home range size for isopleth 95%, you have to 
set the argument percent = 95 in the function NNCH.area. Or, if you want 
the home range sizes for isopleths 100 to 50% by 5% steps, you have to 
set: percent = rev(seq(50,95, by=5)) in the function NNCH.area. 
Similarly, if you want to plot the 95% home range, you have to set 
percent=95 in the function plot.NNCH. etc.
Have a look at the argument percent on the help pages of plot.NNCH, and 
Hope this helps,

Clément Calenge

Cellule d'appui à l'analyse de données
Office national de la chasse et de la faune sauvage
Saint Benoist - 78610 Auffargis
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