Create a data frame of map data.
Arguments
- map
name of map provided by the maps package. These include
county
,france
,italy
,nz
,state
,usa
,world
,world2
.- region
name of subregions to include. Defaults to
.
which includes all subregion. See documentation formap
for more details.- exact
should the
region
be treated as a regular expression (FALSE
) or as a fixed string (TRUE
).- ...
all other arguments passed on to
map
Examples
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)
ggplot(choro, aes(long, lat)) +
geom_polygon(aes(group = group, fill = assault / murder)) +
coord_map("albers", at0 = 45.5, lat1 = 29.5)
}