Added xlim and ylim arguments to borders()

Author: markpayneatwork

R/fortify-map.r

@@ -74,6 +74,7 @@ map_data <- function(map, region = ".", exact = FALSE, ...) {
 #' @param regions map region
 #' @param fill fill colour
 #' @param colour border colour
+#' @param "xlim, ylim" map xlim and ylim,, see \code{\link[maps]{map}} for details
 #' @param ... other arguments passed onto \code{\link{geom_polygon}}
 #' @export
 #' @examples
@@ -92,10 +93,17 @@ map_data <- function(map, region = ".", exact = FALSE, ...) {
 #'   borders("state") +
 #'   geom_point(aes(size = pop)) +
 #'   scale_size_area()
-#'
+#' 
+#' #Same map, with geographical context
+#' data(us.cities)
+#' capitals <- subset(us.cities, capital == 2)
+#' ggplot(capitals,aes(long,lat)) +
+#'   borders("world",xlim=c(-130,-60),ylim=c(20,50))+
+#'   geom_point(aes(size = pop)) +
+#'   scale_size_area()+coord_quickmap(xlim=c(-130,-60),ylim=c(20,50))
 #' }
-borders <- function(database = "world", regions = ".", fill = NA, colour = "grey50", ...) {
-  df <- map_data(database, regions)
+borders <- function(database = "world", regions = ".", fill = NA, colour = "grey50", xlim=NULL,ylim=NULL,...) {
+  df <- map_data(database, regions,xlim=xlim,ylim=ylim)
   geom_polygon(aes_(~long, ~lat, group = ~group), data = df,
     fill = fill, colour = colour, ..., inherit.aes = FALSE)
 }