Map of US Auto Plant Locations

auto_plant_loc.R

# LOAD LIBRARIES ---------------------------------------------------------------
library(ggplot2)
library(maps)

# LOAD DATA --------------------------------------------------------------------
# read data and add column names
auto_plants = read.csv('Data.csv', as.is = TRUE,
    col.names = c('location', 'firm', 'lat', 'long', 'Production', 'temparature'))

# classify firm as others if total plants < 5
auto_plants = ddply(auto_plants, .(firm), mutate,
    num_plants = length(firm),
    Firm   = ifelse(num_plants < 5, 'OTHERS', firm)
)

# get us state map data
us_states = map_data('state')

# construct map of auto plant locations 
auto_map = ggplot(us_states, aes(x = long, y = lat)) +
  geom_polygon(aes(group = group), fill = 'gray80', colour = 'gray') +
  geom_point(data = auto_plants, aes(size = Production, colour = Firm), 
    alpha = 0.7) +
  scale_area(to = c(2, 8)) +
  xlab(NULL) + ylab(NULL) +
  theme_bw() +
  coord_cartesian(xlim = c(-130, -55)) +
  opts(
    legend.position = c(0.90, 0.40),
    panel.border = theme_blank(),
    panel.grid.major = theme_blank(),
    panel.grid.minor = theme_blank(),
    axis.text.x = theme_blank(),
    axis.text.y = theme_blank(),
    axis.ticks  = theme_blank(),
    plot.title  = theme_text(hjust = 0.1, vjust = 1, face = 'bold', size = 20),
    title = 'LOCATION OF AUTO PLANTS IN UNITED STATES')

print(auto_map)
ggsave('auto_plant_map.pdf', auto_map, width = 10, height = 7.