Merge branch 'master' of https://github.com/markpayneatwork/ggplot2 into markpayneatwork-master

Author: hadley

NEWS.md

@@ -337,6 +337,9 @@ version of ggplot.
 
 ## Bug fixes and minor improvements
 
+* `borders()` now accepts xlim and ylim arguments for specifying the geographical 
+  region of interest (@markpayneatwork, #1392)
+
 * All partially matched arguments and `$` have been been replaced with 
   full matches (@jimhester, #1134).
 

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 latitudinal and logitudinal range for extracting map polygons, 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)
 }