plot Taiwan map with R

R_Taiwan_plot.R

library(ggplot2)
library(maptools)
library(xlsx)

countyDat<-data.frame(Eng=c("Taipei","Taipei City","Taoyuan","Taichung","Taichung City","Tainan",
                            "Tainan City","Kaohsiung","Kaohsiung City","Ilan","Hsinchu","Miaoli",
                            "Changhwa","Nantou","Yunlin","Chiayi","Pingtung","Taitung","Hualien",
                            "Penghu","Keelung City","Hsinchu","Chiayi","Kinmen","Lienchiang"
                            
),
Chn=c("新北市","臺北市","桃園市","臺中市","臺中市","臺南市",
      "臺南市","高雄市","高雄市","宜蘭縣","新竹縣","苗栗縣",
      "彰化縣","南投縣","雲林縣","嘉義縣","屏東縣","臺東縣","花蓮縣",
      "澎湖縣","基隆市","新竹市","嘉義市","金門縣","連江縣"
),
stringsAsFactors = F
)

gpclibPermit()
load("/home/ray/R_code/graph/TWN_adm/TWN_adm2.RData")
map <- fortify(gadm,region='ID_2')
map$region <- gadm$NAME_2[match(map$id,gadm$ID_2)]
map <- map[which(map$region!=""),]

# Load Population Data
pdata <- read.xlsx('/home/ray/importData/m0s710405.xls',1)
pdata <-
  data.frame(
    region = as.character(pdata[grep("市|縣",pdata[,1]),1]),
    population = as.numeric(as.character(pdata[grep("市|縣",pdata[,1])-1,3])),
    stringsAsFactors = F)
pdata$region <- countyDat$Eng[match(pdata$region,countyDat$Chn)]
pdata <- pdata[which(pdata$region %in% map$region),]

ggplot(data = pdata) +
  geom_map(map =map,aes(map_id = region, fill = population),
           color='gray40' ) +
  expand_limits(x = map$long, y = map$lat) + 
  scale_fill_continuous(high='red2',low='white') +
  theme(axis.text=element_blank(),
        axis.ticks=element_blank(),
        axis.title=element_blank(),
        panel.grid.major=element_blank(),
        panel.background=element_blank()) +
  labs(title="台灣人口統計")