Selects observations that belong to the time interval of interest and removes
all others. This function also removes entire IDs from the dataset when there
is one or fewer observations at this time interval. This function works
round_track_time to only retain observations
sampled at a regular time interval, which is important for analyzing step
lengths and turning angles. Column storing the time intervals must be labeled
A list of data associated with each animal ID where names of list elements are the ID names.
numeric. The time interval of interest.
A list where observations for each animal ID (element) has been
int. Two columns (
added for each list element (ID), which store the original observation
number before filtering and the new observation number after filtering,
#load data data(tracks) #subset only first track tracks<- tracks[tracks$id == "id1",] #calculate step lengths and turning angles tracks<- prep_data(dat = tracks, coord.names = c("x","y"), id = "id") #round times to nearest interval of interest (e.g. 3600 s or 1 hr) tracks<- round_track_time(dat = tracks, id = "id", int = 3600, tol = 180, time.zone = "UTC", units = "secs") #create list from data frame tracks.list<- df_to_list(dat = tracks, ind = "id") #filter observations to only 1 hr (or 3600 s) tracks_filt.list<- filter_time(dat.list = tracks.list, int = 3600)