A cleaned movement track of one individual at a time can be classified into
residence patches using the
function atl_res_patch.
The function expects a specific organisation of the data: there should be
at least the following columns, x, y, and time,
corresponding to the coordinates, and the time as POSIXct.
atl_res_patch requires only three parameters: (1) the maximum
speed threshold between localizations (called max_speed), (2) the
distance threshold between clusters of positions (called
lim_spat_indep), and (3) the time interval between clusters
(called lim_time_indep).Clusters formed of fewer than a minimum
number of positions can be excluded.The exclusion of clusters with few
positions can help in removing bias due to short stops, but if such short
stops are also of interest, they can be included by reducing the
min_fixes argument.
Usage
atl_res_patch(
data,
max_speed = 3,
lim_spat_indep = 75,
lim_time_indep = 180,
min_fixes = 3,
min_duration = 120
)Arguments
- data
A dataframe of any class that is or extends data.frame of one individual only. The dataframe must contain at least two spatial coordinates,
xandy, and a temporal coordinate,time.- max_speed
A numeric value specifying the maximum speed (m/s) between two coordinates that would be considered non-transitory
- lim_spat_indep
A numeric value of distance in metres of the spatial distance between two patches for them to the considered independent.
- lim_time_indep
A numeric value of time in minutes of the time difference between two patches for them to be considered independent.
- min_fixes
The minimum number of fixes for a group of spatially-proximate number of points to be considered a preliminary residence patch.
- min_duration
The minimum duration (in seconds) for classifying residence patches.