Computes summary statistics of movement data grouped by patches for each individual tag. Calculates spatial and temporal summaries within each patch, distances traveled inside patches, distances and time intervals between patches, displacement within patches, and patch duration. Additional user-specified summary variables and functions can also be applied dynamically.
Arguments
- data
A data.frame or data.table containing movement data. Must include columns:
tag(ID),x,y(coords),time(timestamp), andpatch(patch ID).- summary_variables
Character vector of variable names in
datafor additional summaries. Variables should be numeric or compatible with the summary functions.- summary_functions
Character vector of function name (as single string) to apply to each variable in
summary_variables. Functions must work on numeric vectors (e.g., "mean" or "median").
Value
A data.table with one row per tag and patch containing:
nfixes: Number of fixes in the patch.x_mean,x_median,x_start,x_end: Summary stats of x.y_mean,y_median,y_start,y_end: Summary stats of y.time_mean,time_median,time_start,time_end: Summary stats of time.Additional summaries from
summary_variablesandsummary_functions.dist_in_patch: Total distance (in m) traveled within thepatch.dist_bw_patch: Distance (in m) between end of previous and start of current patch.time_bw_patch: Time (in sec) elapsed between end of previous and start of current patch.disp_in_patch: Straight-line (in m) displacement between start and end of patch.duration: Duration spent (in sec) within the patch.