Create a layer of map borders.

Usage

borders(database = "world", regions = ".", fill = NA, colour = "grey50", xlim = NULL, ylim = NULL, ...)

Arguments

database
map data, see map for details
regions
map region
fill
fill colour
colour
border colour
xlim, ylim
latitudinal and logitudinal range for extracting map polygons, see map for details.
...
other arguments passed onto geom_polygon

Description

Create a layer of map borders.

Examples

if (require("maps")) { ia <- map_data("county", "iowa") mid_range <- function(x) mean(range(x)) seats <- plyr::ddply(ia, "subregion", plyr::colwise(mid_range, c("lat", "long"))) 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) 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() # 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() }