extract borders function

Author: teunbrand

DESCRIPTION

@@ -93,6 +93,7 @@ Collate:
     'compat-plyr.R'
     'utilities.R'
     'aes.R'
+    'annotation-borders.R'
     'utilities-checks.R'
     'legend-draw.R'
     'geom-.R'

R/annotation-borders.R

@@ -0,0 +1,53 @@
+#' Create a layer of map borders
+#'
+#' This is a quick and dirty way to get map data (from the \pkg{maps} package)
+#' onto your plot. This is a good place to start if you need some crude
+#' reference lines, but you'll typically want something more sophisticated
+#' for communication graphics.
+#'
+#' @param database map data, see [maps::map()] for details
+#' @param regions map region
+#' @param fill fill colour
+#' @param colour border colour
+#' @param xlim,ylim latitudinal and longitudinal ranges for extracting map
+#'   polygons, see [maps::map()] for details.
+#' @inheritDotParams geom_polygon
+#' @export
+#' @examples
+#' if (require("maps")) {
+#'
+#' ia <- map_data("county", "iowa")
+#' mid_range <- function(x) mean(range(x))
+#' seats <- do.call(rbind, lapply(split(ia, ia$subregion), function(d) {
+#'   data.frame(lat = mid_range(d$lat), long = mid_range(d$long), subregion = unique(d$subregion))
+#' }))
+#'
+#' ggplot(ia, aes(long, lat)) +
+#'   geom_polygon(aes(group = group), fill = NA, colour = "grey60") +
+#'   geom_text(aes(label = subregion), data = seats, size = 2, angle = 45)
+#' }
+#'
+#' if (require("maps")) {
+#' data(us.cities)
+#' capitals <- subset(us.cities, capital == 2)
+#' ggplot(capitals, aes(long, lat)) +
+#'   borders("state") +
+#'   geom_point(aes(size = pop)) +
+#'   scale_size_area() +
+#'   coord_quickmap()
+#' }
+#'
+#' if (require("maps")) {
+#' # Same map, with some world context
+#' 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()
+#' }
+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(.data$long, .data$lat, group = .data$group), data = df,
+               fill = fill, colour = colour, ..., inherit.aes = FALSE)
+}

R/fortify-map.R

@@ -108,57 +108,3 @@ map_data <- function(map, region = ".", exact = FALSE, ...) {
   df[names(names)] <- vec_slice(names, df$group)
   vec_slice(df, stats::complete.cases(df$lat, df$long))
 }
-
-#' Create a layer of map borders
-#'
-#' This is a quick and dirty way to get map data (from the \pkg{maps} package)
-#' onto your plot. This is a good place to start if you need some crude
-#' reference lines, but you'll typically want something more sophisticated
-#' for communication graphics.
-#'
-#' @param database map data, see [maps::map()] for details
-#' @param regions map region
-#' @param fill fill colour
-#' @param colour border colour
-#' @param xlim,ylim latitudinal and longitudinal ranges for extracting map
-#'   polygons, see [maps::map()] for details.
-#' @inheritDotParams geom_polygon
-#' @export
-#' @examples
-#' if (require("maps")) {
-#'
-#' ia <- map_data("county", "iowa")
-#' mid_range <- function(x) mean(range(x))
-#' seats <- do.call(rbind, lapply(split(ia, ia$subregion), function(d) {
-#'   data.frame(lat = mid_range(d$lat), long = mid_range(d$long), subregion = unique(d$subregion))
-#' }))
-#'
-#' ggplot(ia, aes(long, lat)) +
-#'   geom_polygon(aes(group = group), fill = NA, colour = "grey60") +
-#'   geom_text(aes(label = subregion), data = seats, size = 2, angle = 45)
-#' }
-#'
-#' if (require("maps")) {
-#' data(us.cities)
-#' capitals <- subset(us.cities, capital == 2)
-#' ggplot(capitals, aes(long, lat)) +
-#'   borders("state") +
-#'   geom_point(aes(size = pop)) +
-#'   scale_size_area() +
-#'   coord_quickmap()
-#' }
-#'
-#' if (require("maps")) {
-#' # Same map, with some world context
-#' ggplot(capitals, aes(long, lat)) +
-#'   borders("world", xlim = c(-130, -60), ylim = c(20, 50)) +
-#'   geom_point(aes(size = pop)) +
-#'   scale_size_area() +
-#'   coord_quickmap()
-#' }
-borders <- function(database = "world", regions = ".", fill = NA,
-                    colour = "grey50", xlim = NULL, ylim = NULL, ...) {
-  df <- map_data(database, regions, xlim = xlim, ylim = ylim)
-  geom_polygon(aes(.data$long, .data$lat, group = .data$group), data = df,
-    fill = fill, colour = colour, ..., inherit.aes = FALSE)
-}