[R-sig-eco] adehabitatLT - lavielle segmentation, first passage time

[Pinaud David]

Hi Kylie,
You could use:

l2 <- lavielle(a1_lav[!is.na(a1_lavt$rXX), "rXX"],  Lmin=5,  Kmax=10)
chooseseg(l2)      # K=7 seems ok
fp2 <- findpath(l2,  7)

where a1_lavt is the ouptput from fpt() and a1_lavt$rXX is the FPT 
values at which you observed a peak of variance (=ARS behaviour at XX 
radius)

HTH

David

Le 30/05/2012 14:38, Kylie Scales a écrit :
> Hi all,
>
>
>
> I am using the adehabitatLT package to identify ARS zones in seabird GPS
> tracks, utilising a first passage time approach.  I would like to use the
> lavielle() function to segment tracks, using first passage time at
> appropriate scales as the parameter for segmentation.  I have generated fpt
> at appropriate scales, identified using varlogfpt.   I have an input data
> frame (a1_lav) with x, y, datetime, fpt@*r*km (where x and y are UTM).  I
> have tried:
>
>
>
>> lavielle(a1_lav, Lmin=5, Kmax=10, ld=1, type="meanvar", which="fpt_11km")
>
>
> But get an error message:
>
>
>
> Error in lavielle.default(g151_burst1_lav, Lmin = 5, Kmax = 10, ld = 1,  :
>
>    No missing values allowed in the series
>
>
>
> The fpt vector has several 'NA's at certain scales, which must be the
> missing values.
>
>
>
> Any tips on how to use lavielle() more effectively to automate the process
> of identifying ARS zones using fpt, or a way around the 'NA's issue, would
> be very much appreciated.
>
>
>
> Many thanks,
>
>
>
> Kylie Scales
>
>
> Postgraduate Researcher
>
> Plymouth Marine Laboratory
>
> Prospect Place
>
> Plymouth, UK
> +44 (0)1752 633165
>
> 	[[alternative HTML version deleted]]
>
>
>
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-- 
***************************************************
Dr. David PINAUD
Ingénieur de Recherche "Analyses spatiales"

Centre d'Etudes Biologiques de Chizé - CNRS UPR1934
79360 Villiers-en-Bois, France
poste 485
Tel: +33 (0)5.49.09.35.58
Fax: +33 (0)5.49.09.65.26
http://www.cebc.cnrs.fr/

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