borders {ggplot2} | R Documentation |
Create a layer of map borders
Description
This is a quick and dirty way to get map data (from the 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.
Usage
borders(
database = "world",
regions = ".",
fill = NA,
colour = "grey50",
xlim = NULL,
ylim = NULL,
...
)
Arguments
database |
map data, see maps::map() for details
|
regions |
map region
|
fill |
fill colour
|
colour |
border colour
|
xlim , ylim |
latitudinal and longitudinal ranges for extracting map
polygons, see maps::map() for details.
|
... |
Arguments passed on to geom_polygon
rule Either "evenodd" or "winding" . If polygons with holes are
being drawn (using the subgroup aesthetic) this argument defines how the
hole coordinates are interpreted. See the examples in grid::pathGrob() for
an explanation.
mapping Set of aesthetic mappings created by 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.
data 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. A function can be created
from a formula (e.g. ~ head(.x, 10) ).
stat The statistical transformation to use on the data for this
layer, either as a ggproto Geom subclass or as a string naming the
stat stripped of the stat_ prefix (e.g. "count" rather than
"stat_count" )
position Position adjustment, either as a string naming the adjustment
(e.g. "jitter" to use position_jitter ), or the result of a call to a
position adjustment function. Use the latter if you need to change the
settings of the adjustment.
show.legend 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.
inherit.aes 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() .
na.rm If FALSE , the default, missing values are removed with
a warning. If TRUE , missing values are silently removed.
|
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()
}
[Package
ggplot2 version 3.5.0
Index]