Im trying to use the adehabitat packages in R to analyse GPS data for habitat use and namimal movement, but am running into problem regarding in data format.
My GPS data have been recorded every 30 min so the date will be repeated for every 30 min. Adehabitat seems not to be able handle the repeated date.
Or am I missing something.
Do any of you have experience With this?
Best regards,
Nicolai
Your problem is not so much adehabitat as probably the POSIXct format in R. You have to make sure your date/time conversion is correct. You can use strptime or as.POSIXct in combination with a character vector that contains date AND time. If your data is stored in different columns you have to merge them using paste(). Also beware about the time zone and the OS specific coding of time zone.
Alternatively, you can use movebank.org to store and organise (and share if you want) your data. You get a username and password, upload the data to your account. You will remain the owner of the data. It has a nice data upload gui, so you can map columns and indicate what time zone etc. your data was collected in. Then, you can set the permissions as to who can see or access your data, metadata, raw data and even single individuals can be set to different sharing rights. Make sure you set that to what you think is appropriate. After you uploaded your data, you can use the R library move to load the data in R, calculate things like speed, distances etc or take the data over to adehabitat.
Hi.
Thank you for Your reply. I have tried using the POSIXct format combining both date and time With the same error when using adehabitat, but I|ll give the movebank.org a go to see if i can avoid lots of the problems i face With my relatively uncomplicated data.
I will later enrich them by abiotic factors from a local weather station as well as With reproductive effort data.
Best regards,
Nicolai
You can use as.ltraj in Type II ((time recorded) and as.traj for Type I. I use adehabitat as well (not only adehabitatLT) :
http://127.0.0.1:20085/library/adehabitat/html/as.traj.html
Glad to know that. I wrote a paper about black vulture fledging dispersal using adehabitat (sorry, in Spanish) (https://www.researchgate.net/publication/229429162_PATRONES_DE_MOVIMIENTO_Y_USO_DEL_ESPACIO_EN_LA_DISPERSIN_JUVENIL_DEL_BUITRE_NEGRO_%28Aegypius_monachus%29).
Article Patrones de movimiento y uso del espacio en la dispersión ju...
excellent!
A pity you cant visualize time series dynamically in papers as you can do online :-)
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