Create a data frame of map data
Easily turn data from the maps package in to a data frame suitable for plotting with ggplot2.
map_data(map, region = ".", exact = FALSE, ...)
map |
name of map provided by the maps package. These
include |
region |
name of subregions to include. Defaults to |
exact |
should the |
... |
all other arguments passed on to |
if (require("maps")) {
states <- map_data("state")
arrests <- USArrests
names(arrests) <- tolower(names(arrests))
arrests$region <- tolower(rownames(USArrests))
choro <- merge(states, arrests, sort = FALSE, by = "region")
choro <- choro[order(choro$order), ]
ggplot(choro, aes(long, lat)) +
geom_polygon(aes(group = group, fill = assault)) +
coord_map("albers", at0 = 45.5, lat1 = 29.5)
}
if (require("maps")) {
ggplot(choro, aes(long, lat)) +
geom_polygon(aes(group = group, fill = assault / murder)) +
coord_map("albers", at0 = 45.5, lat1 = 29.5)
}Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.