R/split_emis.R

In vein: Vehicular Emissions Inventories

#' Split street emissions based on a grid
#'
#' @description \code{\link{split_emis}} split street emissions into a grid.
#'
#' @param net A spatial dataframe of class "sp" or "sf". When class is "sp"
#' it is transformed to "sf" with emissions.
#' @param distance Numeric distance or a grid with class "sf".
#' @param add_column Character indicating name of column of distance. For instance,
#' if distance is an sf object, and you wand to add one extra column to the
#' resulting object.
#' @param verbose Logical, to show more information.
#' @importFrom sf st_sf st_as_sf st_length  st_intersection st_set_geometry
#' @export
#' @examples \dontrun{
#' data(net)
#' g <- make_grid(net, 1/102.47/2) #500m in degrees
#' names(net)
#' dim(net)
#' netsf <- sf::st_as_sf(net)[, "ldv"]
#' x <- split_emis(net = netsf, distance = g)
#' dim(x)
#' g$A <- rep(letters, length = 20)[1:nrow(g)]
#' g$B <- rev(g$A)
#' netsf <- sf::st_as_sf(net)[, c("ldv", "hdv")]
#' xx <- split_emis(netsf, g, add_column = c("A", "B"))
#' }
split_emis <- function(net, distance, add_column, verbose = TRUE){
  net <- sf::st_as_sf(net)
  if(is.numeric(distance)){
    if(verbose) cat("Creating grid\n")
    g <- make_grid(spobj = net, width = distance)
  } else if (inherits(distance, "sf")) {
    g <- distance
  }
  net$id <- NULL
  if(verbose){
    sumemis <- sum(sf::st_set_geometry(net, NULL), na.rm = T)/1000
    cat("Total Emissions", sumemis, " kg \n")
  }
  ncolnet <- names(sf::st_set_geometry(net, NULL))
  net$LKM <- sf::st_length(net)
  if(verbose) cat("Intersecting\n")
  gnet <- suppressMessages(suppressWarnings(st_intersection(net, g)))

  # check add_column and store it
  if(!missing(add_column)){
    nc <- list()
      for(i in 1:length(add_column)){
      nc[[i]] <- gnet[[add_column[i]]]
      gnet[[add_column[i]]] <- NULL
    }
  }

  gnet$LKM2 <- sf::st_length(gnet)
  geo <- sf::st_geometry(gnet)
  gnet <- as.data.frame(sf::st_set_geometry(gnet, NULL))
  gnet[, ncolnet] <- gnet[, ncolnet] * as.numeric(gnet$LKM2/gnet$LKM)
  gnet <- as.data.frame(gnet[, ncolnet])
  if(verbose){
    sumemis <- sum(gnet, na.rm = T)/1000
    cat("Total Emissions", sumemis, " kg \n")
  }
  if(!missing(add_column)){
    if(verbose) cat("Adding Column\n")
    for(i in 1:length(add_column)){
      gnet[[add_column[i]]] <- nc[[i]]
    }
  }
names(gnet) <- ncolnet
  gnet$id <- 1:nrow(gnet)
  gnet <- sf::st_sf(gnet, geometry = geo)
  return(gnet)
}