ggplot2::geom_tile()で日本地図

R bologgers (www.r-bloggers.com) で、カナダの地図上にデータをマッピングする例が紹介されていたので、日本用に書いておきます。これくらいのデザインの方が見やすい時もあるので。

---

Library

library(tidyverse)
library(viridis)
library(ggplot2)

Map Info.

# Location Data
JP_plot <- tribble(
    ~Prefecture, ~Code, ~x, ~y,
    "北海道", "HK", 16, 14,
    "青森県",　"AO", 15, 11,
    "岩手県",　"IT", 15, 10,
    "宮城県",　"MG", 15, 9,
    "秋田県",　"AK", 14, 10,
    "山形県",　"YG", 14, 9,
    "福島県",　"FS", 15, 8,
    "茨城県",　"IB", 15, 6,
    "栃木県",　"TC", 15, 7,
    "群馬県",　"GU", 14, 7,
    "埼玉県",　"ST", 14, 6,
    "千葉県",　"CB", 15, 5,
    "東京都",　"TY", 14, 5,
    "神奈川県",　"KN", 14, 4,
    "新潟県",　"NI", 14, 8,
    "富山県",　"TM", 13, 7,
    "石川県",　"IS", 12, 7,
    "福井県",　"FI", 12, 6,
    "山梨県",　"YN", 13, 5,
    "長野県",　"NA", 13, 6,
    "岐阜県",　"GI", 12, 5,
    "静岡県",　"SZ", 13, 4,
    "愛知県",　"AI", 12, 4,
    "三重県",　"ME", 11, 4,
    "滋賀県",　"SI", 11, 5,
    "京都府",　"KY", 10, 5,
    "大阪府",　"OS", 9, 5,
    "兵庫県",　"HG", 8, 5,
    "奈良県",　"NR", 10, 4,
    "和歌山県",　"WA", 9, 4,
    "鳥取県",　"TT", 7, 5,
    "島根県",　"SM", 6, 5,
    "岡山県",　"OY", 7, 4,
    "広島県",　"HS", 6, 4,
    "山口県",　"YA", 5, 5,
    "徳島県",　"TK", 7, 1,
    "香川県",　"KA", 7, 2,
    "愛媛県",　"EH", 6, 2,
    "高知県",　"KO", 6, 1,
    "福岡県",　"FO", 4, 3,
    "佐賀県",　"SG", 3, 3,
    "長崎県",　"NS", 2, 3,
    "熊本県",　"KU", 3, 2,
    "大分県",　"OI", 4, 2,
    "宮崎県",　"MZ", 4, 1,
    "鹿児島県",	"KG", 3, 1,
    "沖縄県",　"OK", 1, 1)

# Define Map sizes
JP_plot$Scale <- c(3,rep(1,46)) #北海道だけ少し大きく

# Abbreviated Prefectues
JP_plot$Prefec <- JP_plot$Prefecture
JP_plot$Prefec <- gsub("県", "", JP_plot$Prefec)  
JP_plot$Prefec <- gsub("府", "", JP_plot$Prefec) 
JP_plot$Prefec <- gsub("東京都", "東京", JP_plot$Prefec) 

Data Preparation

# Fake Data
set.seed(27)
JP_plot$Data <- rnorm(n=47, mean=50, sd=20)

Plot by ggplot2

# Plot
JP_plot %>%
  ggplot(aes(x = x,
             y = y,
             width = Scale,
             height = Scale)) + 
  geom_tile(aes(fill = Data), color = "white") + 
  geom_text(aes(label = Prefec), size = 2.7, color = "white") +  
  
  # Codeをラベルとして表示する場合
  #geom_text(aes(label = Code), size = 2.7, color = "white") + 

  coord_fixed(ratio = 1) + 
  theme(
    panel.background = element_blank(),
    panel.grid = element_blank(), 
    axis.title = element_blank(), 
    axis.text = element_blank(), 
    axis.ticks = element_blank()) + 
　　scale_fill_viridis(na.value = "#E1E1E1", option = "D", begin = 0, end = 1)

　# マニュアルで色（3色）を指定する場合
  # scale_fill_gradient2(low="#777777",
  #                      mid="#DDDDDD",
  #                      high="#2A465C,
  #                      midpoint = 50)

 

https://www.r-bloggers.com/the-tile-grid-map-for-canada/