原文鏈接：http://tecdat.cn/?p=13247

本文我們繪制英國脫歐投票的地圖。第一步是繪制底圖

1. library(sp)

2. library(raster)

3. download.file("http://biogeo.ucdavis.edu/data/gadm2.8/rds/GBR_adm2.rds","GBR_adm2.rds")

4. UK=readRDS("GBR_adm2.rds")

5. UK@data[159,"HASC_2"]="GB.NR"

6. plot(UK, xlim = c(-4,-2), ylim = c(50, 59), main="UK areas")

添加愛爾蘭

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2. plot(IRL,add=TRUE)

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?添加法國，它位于右下方，因此我們應(yīng)該看到一點(diǎn)…

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2. plot(FR,add=TRUE)

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然后，我們可以檢索英國退歐公投數(shù)據(jù)

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2. referendum=ddply(referendum,.(Region,HASC_code),summarise,Remain=sum(Remain),Leave=sum(Leave))

我們可以發(fā)現(xiàn)，脫歐贏得了51.89％的選票

1. > sum(referendum$Leave)/(sum(referendum$Leave)+sum(referendum$Remain))

2. [1] 0.5189184

大家可以看一下，使用

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2. plot(UK, col = map_data$Brexit, border = "gray1", xlim = c(-4,-2), ylim = c(50, 59), main="How the UK has voted?", bg="#A6CAE0")

3. plot(IRL, col = "lightgrey", border = "gray1",add=TRUE)

4. plot(FR, col = "lightgrey", border = "gray1",add=TRUE)

（我們添加了一個小圖例以使其更清晰）。為此，我們可以使用制圖軟件包

1. plot(UK, col = "grey", border = "gray1", xlim = c(-4,-2), ylim = c(50, 59),bg="#A6CAE0")

2. plot(IRL, col = "lightgrey", border = "gray1",add=TRUE)

3. plot(FR, col = "lightgrey", border = "gray1",add=TRUE)

4. choroLayer(spdf = UK,

5. df = map_data,

6. var = "Percentage_Remain",

7. breaks = seq(0,100,10),

8. col = cols,

9. legend.pos = "topright",

10. legend.title.txt = "",

11. legend.values.rnd = 2,

12. add = TRUE)

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