
This is a quick and dirty way to get map data (from the maps package) on to 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.
borders(database = "world", regions = ".", fill = NA,
colour = "grey50", xlim = NULL, ylim = NULL, ...)
map data, see maps::map()
for details
map region
fill colour
border colour
latitudinal and longitudinal ranges for extracting map
polygons, see maps::map()
for details.
Arguments passed on to geom_polygon
Set of aesthetic mappings created by aes()
or
aes_()
. If specified and inherit.aes = TRUE
(the
default), it is combined with the default mapping at the top level of the
plot. You must supply mapping
if there is no plot mapping.
The data to be displayed in this layer. There are three options:
If NULL
, the default, the data is inherited from the plot
data as specified in the call to ggplot()
.
A data.frame
, or other object, will override the plot
data. All objects will be fortified to produce a data frame. See
fortify()
for which variables will be created.
A function
will be called with a single argument,
the plot data. The return value must be a data.frame
, and
will be used as the layer data.
The statistical transformation to use on the data for this layer, as a string.
Position adjustment, either as a string, or the result of a call to a position adjustment function.
logical. Should this layer be included in the legends?
NA
, the default, includes if any aesthetics are mapped.
FALSE
never includes, and TRUE
always includes.
It can also be a named logical vector to finely select the aesthetics to
display.
If FALSE
, overrides the default aesthetics,
rather than combining with them. This is most useful for helper functions
that define both data and aesthetics and shouldn't inherit behaviour from
the default plot specification, e.g. borders()
.
If FALSE
, the default, missing values are removed with
a warning. If TRUE
, missing values are silently removed.
# NOT RUN {
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()
}
# }
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