Calculates SDR for an object of certain class
sdr(x, time_unit = "secs", append_na = TRUE, ...)# S3 method for track_xyt
sdr(x, time_unit = "secs", append_na = TRUE, ...)
[track_xyt] Object to calculate SDR from. Currently implemented
for track_xyt.
[character] Character string giving time unit. Should be
"secs", "mins", or "hours".
[logical] Should NA be appended to the end of the vector?
Ensures length(result) == nrow(x) if appending as a column of x.
Further arguments, none implemented.
Brian J. Smith and Johannes Signer
time_unit defaults to seconds because calculate_sdr()
returns SDR in m^2/s. We assume the user is also working in a projected
CRS with units in meters, thus we expect SDR in m^2/s to be most relevant.
calculate_sdr(), get_displacement()