I don't know the fpt function but I think that the problem is the choose of the radius. Look at
http://lists.faunalia.it/pipermail/animov/2010-August/000646.html Do you know the reference system of your location? Is WGS84? 2013/2/2 Santiago Guallar <[email protected]> > Thank you very much, Sergio. I'll check the package's documentation. > xy <- Xloc[,c("lat","long")] selects the two columns where the coordinates > are (latitude and longitude), so I don't think there's any problem there. > My coordinates are in the decimal system and I'm checking most of the > Atlantic Ocean. Distance is in Km. > > Have a good weekend! > > Santi > > *From:* Sergio Vignali <[email protected]> > *To:* Santiago Guallar <[email protected]>; Animal Movement < > [email protected]> > *Sent:* Friday, February 1, 2013 7:35 PM > > *Subject:* Re: [AniMov] first passage time: format of coordinates > > I think the problem is in the line 4 of your code. You wrote: > xy <- Xloc[,c("lat","long")] > but you have to select only the coordinates, not all the object Xloc. > > What's the reference system of your coordinates? What's your area of study? > You have to use metric system if you want metric distance in the ltraj > object. > See also AdehabitatLT package and the relative documentation > > > https://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CD4QFjAB&url=http%3A%2F%2Fcran.r-project.org%2Fweb%2Fpackages%2FadehabitatLT%2Fvignettes%2FadehabitatLT.pdf&ei=wAgMUcClKKiR4ATDxYCIBg&usg=AFQjCNEQPXZ8fO_qNTPyyR7BDnViFGbmWg&sig2=vv3VeQ-lr4Hhkiavq3Uujw&bvm=bv.41867550,d.bGE > > When I opened your link I didn't see anything, it's empty, there's not > your tr1.txt file. > > 2013/2/1 Santiago Guallar <[email protected]> > > Hi Sergio, > > No, I don't use qgis just R. > > It's too bad that you can't open the link. Let me show you the head of > object Xloc, see if you can figure out if the the format of the coordinates > xy: > > fix date hm secs trn1 trn2 lat complat long dist > 1 noon 07/06/2007 13:15 39240.55 06:18 20:12 20.25 20.25 19.05 > 0.00 > 2 midnight 08/06/2007 00:59 39241.04 05:46 20:12 27.27 24.31 15.03 0.00 > 3 noon 08/06/2007 13:03 39241.54 05:46 20:20 28.81 28.02 16.00 228.65 > 4 midnight 09/06/2007 01:03 39242.04 05:46 20:20 28.76 28.76 15.98 44.41 > 5 noon 09/06/2007 12:59 39242.54 05:46 20:12 27.12 27.92 14.96 73.77 > 6 midnight 10/06/2007 00:59 39243.04 05:46 20:12 27.07 27.07 14.93 51.02 > head veloc conf jul Date ind > 1 0.00 0.00 9 13671 2007-06-07 13:15:00 2298001 > 2 0.00 0.00 9 13672 2007-06-08 00:59:00 2298001 > 3 13.21 18.95 9 13672 2007-06-08 13:03:00 2298001 > 4 -1.36 3.70 9 13673 2007-06-09 01:03:00 2298001 > 5 46.90 6.18 9 13673 2007-06-09 12:59:00 2298001 > 6 1.79 4.25 9 13674 2007-06-10 00:59:00 2298001 > tr1 seems to be fine: > > *********** List of class ltraj *********** > Type of the traject: Type II (time recorded) > Irregular traject. Variable time lag between two locs > Characteristics of the bursts: > id burst nb.reloc NAs date.begin date.end > 1 2298001 2298001 587 0 2007-06-07 15:15:00 2008-04-30 03:10:00 > But object F is full of NAs: > List of 1 > $ :'data.frame': 587 obs. of 30 variables: > ..$ r1 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > ..$ r2 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > ..$ r3 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > ..$ r4 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > ..$ r5 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > ..$ r6 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > ..$ r7 : num [1:587] NA NA NA NA NA NA NA NA NA NA ... > . > . > . > . > Do you think coordinates format is the problem here? > > Thank you, > > Santi > > > *From:* Sergio Vignali <[email protected]> > *To:* Santiago Guallar <[email protected]>; Animal Movement < > [email protected]> > *Sent:* Thursday, January 31, 2013 7:41 PM > *Subject:* Re: [AniMov] first passage time: format of coordinates > > Hi, > do you usually use QGIS? > You can convert your coordinates with qgis of course! > PS I can't open your link. > > Regards > 2013/1/31 Santiago Guallar <[email protected]> > > > Hello, > > I am trying to create a ltraj object to obtain first passage times (with > the aim to reveal stopover sites of migratory seabirds) using package > adehabitat, My code is: > > require(adehabitat) > Xloc$Date <- paste( Xloc$date, Xloc$hm) > Xloc$Date <- as.POSIXct( Xloc$Date, format = "%d/%m/%Y %H:%M", tz = "GMT" > ) > xy <- Xloc[,c("lat","long")] > id= Xloc$ind > tr1 <- as.ltraj( xy, Xloc$Date, id ) > F <- fpt(tr1, seq(300,1000, length=30)) > plot(F, scale = 500, warn = FALSE) > > However, I only obtain NAs. I think the problem lies in the format of the > coordinates. I'm using a decimal format but function fpt() apparently works > with UTM coordinates. How can I convert them into this format? > Here is a link to a dput() to file tr1.txt: > http://file-manager.000webhost.com/file-manager/index.php > > Thank you for your help! > > Santi > > > > > _______________________________________________ > AniMov mailing list > [email protected] > http://lists.faunalia.it/cgi-bin/mailman/listinfo/animov > > > > > -- > Sergio Vignali > CERM Centro Rapaci Minacciati > (Endangered Raptors Centre) > > > > > > > > -- > Sergio Vignali > CERM Centro Rapaci Minacciati > (Endangered Raptors Centre) > > > -- Sergio Vignali CERM Centro Rapaci Minacciati (Endangered Raptors Centre)
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