# Map plots

## USA Arrests

Examples from http://docs.ggplot2.org/current/geom_map.html.

    library(ggplot2)
    crimes <- data.frame(state = tolower(rownames(USArrests)), USArrests)
    library(reshape2) # for melt
    crimesm <- melt(crimes, id = 1)
    library(maps)

    ##
    ## Attaching package: 'maps'

    ## The following object is masked from 'package:plyr':
    ##
    ##     ozone

    states_map <- map_data("state")
    ggplot(crimes, aes(map_id = state)) + geom_map(aes(fill = Murder), map = states_map) + expand_limits(x = states_map$long, y = states_map$lat)
    last_plot() + coord_map()
    ggplot(crimesm, aes(map_id = state)) + geom_map(aes(fill = value), map = states_map) + expand_limits(x = states_map$long, y = states_map$lat) + facet_wrap( ~ variable)
    great_lakes_states = c('michigan', 'illinois', 'ohio', 'wisconsin', 'indiana')
    great_lakes_map = subset(states_map, region %in% great_lakes_states)
    ggplot(subset(crimesm, state %in% great_lakes_states), aes(map_id = state)) + geom_map(aes(fill = value), map = great_lakes_map) + expand_limits(x=great_lakes_map$long, y=great_lakes_map$lat) + facet_wrap( ~ variable)

Author: Jim Hester Created: 2013 Mar 28 02:44:48 PM Last Modified: 2014 Apr 17 04:53:36 PM