R/splitLines.R

In jmt2080ad/polylineSplitter: Split lines into segments

#' @title Split Lines
#' @description to be filled
#' @param spobj sp object
#' @param dist distance in units of coords
#' @param start start from the start (T) or the end (F)
#' @return spatialLinesDataFrame
#' @import sp
#' @import plyr
#' @export
splitLines<- function(spobj, dist, start = T, sf = F){
    xydf<-coordBuild(spobj)
    if (start == F){
        xydf<-xydf[rev(rownames(xydf)),]
    }
    spoints <- split(xydf, dist)
    linelist <- list()
    lineslist <- list()
    id <- 1
    if(!sf) {
        j <- 1
        for(i in 1:(nrow(spoints)-1)){
            linelist[j] <- Line(spoints[c(i, i + 1), c(1:2)])
            j = j + 1
            if(spoints[i+1,3] == 1){ 
                lineslist[id]<-Lines(linelist, ID = id)
                id = id+1
                linelist<-list()
                j = 1
            }
        }
        return(SpatialLinesDataFrame(SpatialLines(lineslist), data = data.frame(id = 0:(length(lineslist)-1))))
    } else {
        start <- 1
        for(i in 1:(nrow(spoints)-1)){
            if(spoints[i+1,3] == 1){ 
                lineslist[[id]] <- sf::st_linestring(as.matrix(spoints[c(start:(i + 1)), c(1:2)], ncol = 2))
                id <- id + 1
                start <- i + 1
            }
        }
        return(sf::st_sf(id = 1:length(lineslist), geom = sf::st_sfc(lineslist)))
    }
}