R/turnAngle.R

In move: Visualizing and Analyzing Animal Track Data

setGeneric("turnAngleGc", function(x) {
  standardGeneric("turnAngleGc")
})
setMethod("turnAngleGc",
  signature = ".MoveTrackSingle",
  definition = function(x) {
    if (!isLonLat(x)) {
      warning("turnAngleGc is probably not a valid calculation on this projection")
    }
    fb <- finalBearing(x[-n.locs(x), ], x[-1, ])[-(n.locs(x) - 1)]
    b <- bearing(x[-n.locs(x), ], x[-1, ])[-1]
    t <- (b - ((fb)))
    return(((t + 180) %% 360) - 180)
  }
)
setMethod("turnAngleGc",
  signature = ".MoveTrackStack",
  definition = function(x) {
    if (!isLonLat(x)) {
      warning("turnAngleGc is probably not a valid calculation on this projection")
    }
    return(lapply(split(x), turnAngleGc))
  }
)