Nicolas, Thanks heaps for the quick reply! Turns out, in the meantime I finally realized that my id column for some reasons contained 21 levels instead of 20 (I have 20 individuals) (the problem occurred because one of the level was "id", ie the column name, even though I am not sure how that happened...). So I fixed this problem and now my id column is alright (with 20 levels as I wanted); however, now when I run the code again, it comes up with a new error: " Error in as.ltraj(xy = data[, c("X.Latitude", "X.Longitude")], date = data$timestamp, : non unique dates for a given burst". I have looked at the forums and saw that this situation could occur when the date format was not set right (e.g. %y instead of %y) but I carefully checked my format and cannot see any mistake there!
Here is my new code #set working directory setwd("C:/Users/Elodie/Documents/Deakin/Data analysis/GPS data analysis/Processed LB multiple tracks") file_list<-list.files(pattern="*.csv", full.names=TRUE) require(data.table) dataset = rbindlist(lapply( file_list, fread )) write.csv(dataset, file = "dataset_multiple_trips_LB.csv", row.names = F) data<-read.csv("dataset_multiple_trips_LB.csv", header=T) ## FOR SOME REASON, I do not understand why R as automoatically put an "X" in front of some column names (like Date, Time, Latitude, Longitude) but not in front of all of #them (the column name for id stayed as is...) so I just used the names as they appeared in my data frame... timestamp <- as.POSIXct(strptime(as.character(paste(data$X.Date, data$X.Time)),"%Y/%m/%d %H:%M:%S"), "GMT") data <- data.frame(data, timestamp = timestamp) everybody<-as.ltraj(xy = data[,c("X.Latitude","X.Longitude")], date = data$timestamp, id = data$id) Perhaps it could help if I included some of the data so you can see how it looks like: id Index X.Date X.Time X.Latitude X.Longitude X.Speed X.Course X.Distance X.EHPE timestamp LB-LP0009-(2) 38 2013/10/15 05:09:35 -38.621288 142.933365 0 348 0 5072 15/10/2013 5:09 LB-LP0009-(2) 39 2013/10/15 05:11:39 -38.618813 142.935715 0 36 342.725368 4768 15/10/2013 5:11 LB-LP0009-(2) 40 2013/10/15 05:13:49 -38.619331 142.9366 7344 243 96.122993 4768 15/10/2013 5:13 Thanks for letting me know if you can think of a way to fix this! P-S: Fyi, when I apply the drop_level on the code as it was before I fixed the number of levels, I got this: warnings() Warning messages: 1: In Ops.factor(x1$x, x2$x) : - not meaningful for factors 2: In Ops.factor(x1$y, x2$y) : - not meaningful for factors 3: In Ops.factor(x$x, x$x[1]) : - not meaningful for factors 4: In Ops.factor(x$y, x$y[1]) : - not meaningful for factors 5: In Ops.factor(x1$x, x2$x) : - not meaningful for factors 6: In Ops.factor(x1$y, x2$y) : - not meaningful for factors...... There were 50 or more warnings. Elodie Camprasse 6/187 Auburn Road Hawthorn, VIC 3122 Australia Email: elodie.campra...@gmail.com Website: http://hors-des-sentiers-battus.e-monsite.com/ Mobile: (+61) 049 794 0793 -----Original Message----- From: AniMov [mailto:animov-boun...@faunalia.it] On Behalf Of animov-requ...@faunalia.it Sent: Tuesday, 8 July 2014 7:07 PM To: animov@faunalia.it Subject: AniMov Digest, Vol 101, Issue 1 Send AniMov mailing list submissions to animov@faunalia.it To subscribe or unsubscribe via the World Wide Web, visit http://lists.faunalia.it/cgi-bin/mailman/listinfo/animov or, via email, send a message with subject or body 'help' to animov-requ...@faunalia.it You can reach the person managing the list at animov-ow...@faunalia.it When replying, please edit your Subject line so it is more specific than "Re: Contents of AniMov digest..." Today's Topics: 1. Cannot create ltraj object (Elodie Camprasse) 2. Re: Cannot create ltraj object (Morellet Nicolas) ---------------------------------------------------------------------- Message: 1 Date: Tue, 8 Jul 2014 18:21:40 +1000 From: "Elodie Camprasse" <elodie.campra...@gmail.com> To: <animov@faunalia.it> Subject: [AniMov] Cannot create ltraj object Message-ID: <019c01cf9a85$a6f314b0$f4d93e10$@gmail.com> Content-Type: text/plain; charset="us-ascii" Folks, I have been encountering a problem when using the adehabitatLT package and specifically the function as.ltraj and I was hoping someone could give me a clue on how to solve the problem! I am working with GPS data. I have got 20 different files with tracks that I have merged together; it looks like I have successfully created a POSIXct column that I added to the dataframe and I have one column with latitude and one with longitude, as well as an ID column that has the ID of my individual birds; however, when I use the as.ltraj function, I get the following error: "Error in as.ltraj(xy = data_used[, c("latitude", "longitude")], date = data_used$timestamp, : some id's are not present in the data" I tried different things (without naming the columns first and with column names, with or without "-" in the ID numbers, using just the relevant columns with no additional information.) and nothing is fixing the problem. I also do not understand the error message because when I check the length of the relevant columns, there are the same. Here is my code: setwd("C:/Users/Elodie/Documents/Deakin/Data analysis/GPS data analysis/Processed LB multiple tracks") file_list<-list.files(pattern="*.csv", full.names=TRUE) require(data.table) #merge all the files in the working directory in one dataframe dataset = rbindlist(lapply( file_list, fread )) write.csv(dataset, file = "dataset_multiple_trips_LB.csv", row.names = F) data<-read.csv("dataset_multiple_trips_LB.csv", header=F) data_used<-data[-1,] #V3 is the Date column, V4 is the Time column timestamp <- as.POSIXct(strptime(as.character(paste(data_used$V3, data_used$V4)),"%Y/%m/%d %H:%M:%S"), "GMT") data_used <- data.frame(data_used, V11 = timestamp) colnames(data_used)<-c("id", "index", "date", "time", "latitude", "longitude", "speed", "course", "distance", "EHPE", "timestamp") everybody<-as.ltraj(xy = data_used[,c("latitude","longitude")], date = data_used$timestamp, id = data_used$id) Error in as.ltraj(xy = data_used[, c("latitude", "longitude")], date = data_used$timestamp, : some id's are not present in the data If I do the following code, I get the following results > length(data_used$id) [1] 14444 > length(data_used$timestamp) [1] 14444 > length(data_used$longitude) [1] 14444 > length(data_used$latitude) [1] 14444. Thanks in advance for pointing me in the right direction! Elodie Elodie Camprasse 6/187 Auburn Road Hawthorn, VIC 3122 Australia Email: <mailto:elodie.campra...@gmail.com> elodie.campra...@gmail.com Website: <http://hors-des-sentiers-battus.e-monsite.com/> http://hors-des-sentiers-battus.e-monsite.com/ Mobile: <tel:%28%2B61%29%20049%20794%200793> (+61) 049 794 0793 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.faunalia.it/pipermail/animov/attachments/20140708/180cd72f/att achment-0001.html> ------------------------------ Message: 2 Date: Tue, 08 Jul 2014 11:06:54 +0200 From: Morellet Nicolas <nicolas.morel...@toulouse.inra.fr> To: animov@faunalia.it Subject: Re: [AniMov] Cannot create ltraj object Message-ID: <53bbb4ae.9000...@toulouse.inra.fr> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" Hello Elodie, Could you try ? data_used = droplevels(data_used) Maybe some individuals are present in the id variable (if this is a factor variable) but with missing component(s). Cheers, Nicolas. Le 08/07/2014 10:21, Elodie Camprasse a ?crit : > > Folks, > > I have been encountering a problem when using the adehabitatLT package > and specifically the function as.ltraj and I was hoping someone could > give me a clue on how to solve the problem! > > I am working with GPS data. I have got 20 different files with tracks that I have merged together; it looks like I have successfully created a POSIXct column that I added to the dataframe and I have one column with latitude and one with longitude, as well as an ID column that has the ID of my individual birds; however, when I use the as.ltraj function, I get the following error: "Error in as.ltraj(xy = data_used[, c("latitude", "longitude")], date = data_used$timestamp, : > > some id's are not present in the data" > > I tried different things (without naming the columns first and with > column names, with or without "-" in the ID numbers, using just the > relevant columns with no additional information...) and nothing is > fixing the problem. I also do not understand the error message because > when I check the length of the relevant columns, there are the same. > > Here is my code: > > setwd("C:/Users/Elodie/Documents/Deakin/Data analysis/GPS data > analysis/Processed LB multiple tracks") > > file_list<-list.files(pattern="*.csv", full.names=TRUE) > > require(data.table) > > #merge all the files in the working directory in one dataframe > > dataset = rbindlist(lapply( file_list, fread )) > > write.csv(dataset, file = "dataset_multiple_trips_LB.csv", row.names = > F) > > data<-read.csv("dataset_multiple_trips_LB.csv", header=F) > > data_used<-data[-1,] > > #V3 is the Date column, V4 is the Time column > > timestamp <- as.POSIXct(strptime(as.character(paste(data_used$V3, > data_used$V4)),"%Y/%m/%d %H:%M:%S"), "GMT") > > data_used <- data.frame(data_used, V11 = timestamp) > > colnames(data_used)<-c("id", "index", "date", "time", "latitude", > "longitude", "speed", "course", "distance", "EHPE", "timestamp") > > everybody<-as.ltraj(xy = data_used[,c("latitude","longitude")], date = > data_used$timestamp, id = data_used$id) > > Error in as.ltraj(xy = data_used[, c("latitude", "longitude")], date = data_used$timestamp, : > some id's are not present in the data > > If I do the following code, I get the following results > > >length(data_used$id) > [1] 14444 > >length(data_used$timestamp) > [1] 14444 > >length(data_used$longitude) > [1] 14444 > >length(data_used$latitude) > [1] 14444. > > Thanks in advance for pointing me in the right direction! > Elodie > > Elodie Camprasse > > 6/187 Auburn Road > > Hawthorn, VIC 3122 > > Australia > > Email: elodie.campra...@gmail.com <mailto:elodie.campra...@gmail.com> > > Website: http://hors-des-sentiers-battus.e-monsite.com/ > > Mobile: (+61) 049 794 0793 <tel:%28%2B61%29%20049%20794%200793> > > > > _______________________________________________ > AniMov mailing list > AniMov@faunalia.it > http://lists.faunalia.it/cgi-bin/mailman/listinfo/animov -- ********************************************************** Nicolas MORELLET I.N.R.A. - Centre de Recherches de Toulouse Comportement et ?cologie de la Faune Sauvage (C.E.F.S.) BP 52627 - 31326 Castanet-Tolosan cedex (France) Tel : 05.61.28.51.28 Fax : 05.61.28.55.00 ********************************************************** --- Ce courrier ?lectronique ne contient aucun virus ou logiciel malveillant parce que la protection avast! Antivirus est active. http://www.avast.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.faunalia.it/pipermail/animov/attachments/20140708/23f6544d/att achment.html> ------------------------------ Subject: Digest Footer _______________________________________________ AniMov mailing list AniMov@faunalia.it http://lists.faunalia.it/cgi-bin/mailman/listinfo/animov ------------------------------ End of AniMov Digest, Vol 101, Issue 1 ************************************** _______________________________________________ AniMov mailing list AniMov@faunalia.it http://lists.faunalia.it/cgi-bin/mailman/listinfo/animov