R/seglength.R

In move: Visualizing and Analyzing Animal Track Data

setGeneric("seglength", function(x){standardGeneric("seglength")})
setMethod("seglength", 
          signature="SpatialPointsDataFrame",
          definition=function(x){  
          #  track <- coordinates(x)
          #  segM <- cbind(as.data.frame(track)[-nrow(track),], as.data.frame(track)[-1,])
          #  if(isLonLat(x)){
          #    #if proj is long lat the segment lengths are calculated as kilometers on a great circle
          #    Dists <- as.numeric(apply(segM, 1, function(segM) spDistsN1(as.matrix(t(segM[1:2])), as.matrix(t(segM[3:4])), longlat=T)))
          #  } else {
          #    #if proj is not longlat the segmentlength are calculate as (p^2+^2)^1/2
          #    Dists <- sqrt(rowSums((coordinates(x)[-n.locs(x),]-coordinates(x)[-1,])^2))
          #  }
	    Dists<-raster::pointDistance(x[-sum(n.locs(x)),], x[-1,], longlat=isLonLat(x))
            return(Dists)
          })