as.ltraj in adehabitat
Hello,
many thanks for replying ! In the example there are 4 observations for 18/06/2006, at 4 different times, 2 observations for 05/09/2006 at two different times andso on. My data are in excel files, one per individual.
I use this code to read in and prepare the example data set:
library(PBSmapping)
library(adehabitat)
track_1646=read.table("AllChange_1646R.txt", sep="\t", header=TRUE)
attr(track_1646, "projection") <- c("LL")
track_1646.utm <- convUL(track_1646)
track_1646 <- track_1646.utm
#colnames(track_1646) <- c("X","Y","date","id","burst","Time","ID","VR2number")
id <- as.character(track_1646$id)
burst <- as.character(track_1646$burst)
date <- as.POSIXct(strptime(as.character(track_1646$date),"%d/%m/%Y"))
as.ltraj(track_1646, date, id, burst,typeII = TRUE, slsp = c("remove", "missing"))
The last line yields the error message. I am not really sure about the burst argument, and I do not know why as.traj () needs it. Can you shed light on this ?
Many thanks for your time.
Juliane
From: St?phane Dray [dray at biomserv.univ-lyon1.fr]
Sent: 27 March 2009 15:01
To: Struve, Juliane
Cc: r-sig-ecology at r-project.org
Subject: Re: [R-sig-eco] as.ltraj in adehabitat
Sent: 27 March 2009 15:01
To: Struve, Juliane
Cc: r-sig-ecology at r-project.org
Subject: Re: [R-sig-eco] as.ltraj in adehabitat
Juliane,
it seems that you have two relocations observed at the same time.
Without details (e.g., what did you type in R), it is difficult to give
you a more precised answer.
Cheers.
Struve, Juliane wrote:
> Dear list,
>
> I am trying to convert a dataframe into an ltraj object and have a hard time defing the burst argument. The data consist of locations, dates and time for only one individual (id=1646). An example is given below. The individual may have been seen several times during one day at several different locations. When I try to convert the dataframe I get error message
>
> Error in as.ltraj(track_1646, date, id, burst, typeII = TRUE, slsp = c("remove", :
> non unique dates for a given burst
> Would somebody be able to help ?
>
> Thank you very much for your time.
>
> Juliane
>
>
> X Y date id burst Time ID VR2number
> -82.5632 27.303 18/08/2006 1646 1646 08:48:59 64 32
> -82.5605 27.30237 18/08/2006 1646 1646 09:53:20 63 30
> -82.5632 27.303 18/08/2006 1646 1646 13:27:48 121 32
> -82.5737 27.31475 18/08/2006 1646 1646 20:39:18 91 33
> -82.5445 27.27731 05/09/2006 1646 1646 22:17:52 3243 19
> -82.5356 27.2716 05/09/2006 1646 1646 23:29:38 16319 20
> -82.5445 27.27731 08/09/2006 1646 1646 23:34:30 3904 19
> -82.5356 27.2716 09/09/2006 1646 1646 02:39:48 25023 20
>
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--
St?phane DRAY (dray at biomserv.univ-lyon1.fr )
Laboratoire BBE-CNRS-UMR-5558, Univ. C. Bernard - Lyon I
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