Time lags between the locations of a movement track

Calculates the time lags between consecutive locations of a track.

Usage

# S4 method for class '.MoveTrackSingle'
timeLag(x,...)
  # S4 method for class '.MoveTrackStack'
timeLag(x,units, ...)

Arguments

x: a move, moveStack or moveBurst object
units: The units used for the conversion (e.g. "secs", "mins", "hours", "days" or "weeks"). They should be specified for a moveStack to ensure the same units between individuals. Optional (but recommended).
...: Currently not implemented.

Details

Optionally the argument units can be passed on to ensure the time lag is in a certain unit, this is especially useful in case of a moveStack. For more information on the units argument see the help of difftime.

Value

Time lags in the specified units.

If a move or moveBurst object is provided, a numeric vector one element shorter than the number of locations is obtained.
If a moveStack object is provided, a list with one element per individual containing a numeric vector one element shorter than the number of locations is obtained.

Author

Bart Kranstauber & Anne Scharf

Examples

## time lags from a Move object 
data(leroy)
head(timeLag(leroy, units="hours"))
#> [1] 0.2480556 0.2363883 0.2408344 0.2508331 0.2483333 0.2566664
# to add this information to the move object, a "NA" has to be assigened
# e.g. to the first location (it also could be assigend to the first location).
leroy$timeLag <- c(timeLag(leroy, units="hours"), NA)

## time lags from a MoveStack object
data(fishers)
str(timeLag(fishers, units="mins"))
#> List of 2
#>  $ Leroy  : num [1:918] 14.9 14.2 14.5 15 14.9 ...
#>  $ Ricky.T: num [1:999] 27.55 2.55 1.883 2.217 0.583 ...
# to add this information to the moveStack object, a "NA" has to be assigened
# e.g. to the duration is assigned to the first location of each segment
fishers$timeLag <- unlist(lapply(timeLag(fishers, units="mins"),  c, NA))