code by Arthur Charpentier and Timothée Giraud to plot a map of the 'Brexit' vote results -- see sources in the comments

brexit.R

library(sp)
library(raster)
library(rgeos)

## import des données

download.file(url = "http://biogeo.ucdavis.edu/data/gadm2.8/rds/GBR_adm2.rds", 
              destfile = file.path(tempdir(), "GBR_adm2.rds"))
download.file(url = "http://biogeo.ucdavis.edu/data/gadm2.8/rds/IRL_adm0.rds",
              file.path(tempdir(),"IRL_adm0.rds"))
download.file(url = "http://biogeo.ucdavis.edu/data/gadm2.8/rds/FRA_adm0.rds",
              file.path(tempdir(),"FRA_adm0.rds"))
UK <- readRDS(file.path(tempdir(),"GBR_adm2.rds"))
IRL <- readRDS(file.path(tempdir(),"IRL_adm0.rds"))
FR <- readRDS(file.path(tempdir(),"FRA_adm0.rds"))
loc <- "https://f.hypotheses.org/wp-content/blogs.dir/253/files/2016/12/EU-referendum-result-data.csv"
referendum <-read.csv(loc,header=TRUE,dec=".",sep=",",stringsAsFactors = FALSE)


## Manipulation/transformation des données

# correction d'un code
UK[159,"HASC_2"]="GB.NR"
# changement de projection
UK <- spTransform(UK, CRSobj = "+init=epsg:3035")
IRL <- spTransform(IRL, CRSobj = "+init=epsg:3035")
FR <- spTransform(FR, CRSobj = "+init=epsg:3035")

# agrégation des unités d'Irlande du Nord
UK[UK$NAME_1=="Northern Ireland", "HASC_2" ] <- "Northern Ireland"
UK <- rgeos::gUnaryUnion(spgeom = UK, id = UK$HASC_2)
ids <- sapply(methods::slot(UK, "polygons"),methods::slot, "ID")
UK <- SpatialPolygonsDataFrame(Sr = UK, 
                               data = data.frame(id = ids, row.names = ids))

# agrégation des données du referendum
referendum <-referendum[c(3,6,13,14)]
referendum <- aggregate(referendum[, 3:4], 
                        by = list(HASC_code = referendum$HASC_code, 
                                  Region = referendum$Region), 
                        FUN = sum)
referendum <- referendum[referendum$HASC_code != "Gibraltar", ]
referendum[referendum$Remain>referendum$Leave, "brexit"] <- "Remain"
referendum[referendum$Remain<referendum$Leave, "brexit"] <- "Leave"
referendum$nvote <- referendum$Leave + referendum$Remain
referendum$shareLeave <- 100 * referendum$Leave / referendum$nvote



library(cartography)

png("majo.png", width = 450, height = 600, res = 100)
par(mar = c(0,0,1.2,0))
plot(UK, ylim = c(3100000, 4100000), xlim = c(2950000, 3750000), 
     col = NA, border = NA, bg = "#A6CAE0")
plot(IRL, col = "lightgrey", border = NA, add=TRUE)
plot(FR, col = "lightgrey", border = NA, add=TRUE)
typoLayer(spdf = UK, spdfid = "id", 
          df = referendum, dfid = "HASC_code", 
          var = "brexit", 
          col = c("#5A9C50", "#EC4E49"), 
          legend.pos = 'topleft',
          legend.title.txt = "", 
          add = TRUE)
layoutLayer(title = "Vote majoritaire au référendum sur le brexit", 
            sources = "", author = "sources : ??? + GADM2.8", 
            theme = "blue.pal", scale = 100)
dev.off()




png("shareleave.png", width = 450, height = 600, res = 100)
par(mar = c(0,0,1.2,0))
plot(UK, ylim = c(3100000, 4100000), xlim = c(2950000, 3750000), 
     col = NA, border = NA, bg = "#A6CAE0")
plot(IRL, col = "lightgrey", border = NA, add=TRUE)
plot(FR, col = "lightgrey", border = NA, add=TRUE)
# limites des classes
bks <- c(min(referendum$shareLeave), 
         seq(30,70,10), 
         max(referendum$shareLeave))
# palette de couleur
cols <- carto.pal(pal1 = "green.pal", n1 = 3, 
                  pal2 = "red.pal", n2 = 3)
choroLayer(spdf = UK, spdfid = "id", 
          df = referendum, dfid = "HASC_code", 
          var = "shareLeave", breaks = bks,
          col = cols, 
          legend.pos = 'topleft',
          legend.title.txt = "Part du vote 'leave'\n (en %)", 
          add = TRUE)
layoutLayer(title = "Part du 'Leave' au référendum sur le brexit", 
            sources = "", author = "sources : ??? + GADM2.8", 
            theme = "blue.pal", scale = 100)
dev.off()


png("shareleaveprop.png", width = 450, height = 600, res = 100)
par(mar = c(0,0,1.2,0))
plot(UK, ylim = c(3100000, 4100000), xlim = c(2950000, 3750000), 
     col = "grey50",  border = "grey80",lwd = 0.5, bg = "#A6CAE0")
plot(IRL, col = "lightgrey", border = NA, add=TRUE)
plot(FR, col = "lightgrey", border = NA, add=TRUE)
propSymbolsChoroLayer(spdf = UK, spdfid = "id", 
                      df = referendum, dfid = "HASC_code", 
                      var = "nvote",inches = 0.2, 
                      var2 = 'shareLeave',
                      breaks = bks,
                      col = cols)
layoutLayer(title = "Répartition et part du 'Leave' au référendum sur le brexit", 
            sources = "", author = "sources : ??? + GADM2.8", 
            theme = "blue.pal", scale = 100)
text(x = 3018138, y = 3255515, 
     font = 2, srt = 33, cex = 1, pos = 4,
     labels = "La carte n'est pas lisible\ndans la région de Londres")
dev.off()


# library(devtools)
# install_github('riatelab/mapinsetr')
library(mapinsetr)
# définition d'une bounding box autour de la région de Londres
bb <- matrix(data = c(3598988, 3648341, 3177688, 3221347), 
             nrow = 2, ncol = , byrow = T  )
# création d'un masque destiné à extraire les unités londoniennes
londonMask <- create_mask(bb = bb,
                          add = FALSE, 
                          prj = UK@proj4string)
# déplacement et redimensionnement des unités
zoomLondon <- move_and_resize(spdf = UK, 
                              mask = londonMask, 
                              xy = c(3001055, 3196670), 
                              k = 4)
# déplacement et redimensionnement du masque
zoomBox <- move_and_resize(spdf = londonMask, 
                           mask = londonMask, 
                           xy = c(3001055, 3196670), 
                           k = 4)
# fusion du fond de carte initial et du zoom
UK2 <- inset_rbinder(list(UK, zoomLondon))
# affichage du fond de carte
png("UK2.png", width = 450, height = 600, res = 100)
par(mar = c(0,0,1.2,0))
plot(UK2)
layoutLayer("Fond de carte UK avec zoom sur Londres", scale = NULL, 
            north = FALSE, sources = "", author = "")
dev.off()


png("shareleaveprop2.png", width = 450, height = 600, res = 100)
par(mar = c(0,0,1.2,0))
plot(FR, ylim = c(3100000, 4100000), xlim = c(2950000, 3750000), 
     col = 'lightgrey', border = NA, bg = "#A6CAE0")
plot(IRL, col = "lightgrey", border = NA, add=TRUE)
plot(UK2, col = "grey50", border = "grey80",lwd = 0.5,  add=TRUE)
plot(zoomBox, lwd = 1, add=T)
text(x = 3001055, y = 3196670, labels = "Zoom sur Londres", 
     adj = c(0,1.5), cex = 0.7 )
propSymbolsChoroLayer(spdf = UK2, spdfid = "id", 
                      df = referendum, dfid = "HASC_code", 
                      var = "nvote",inches = 0.2, 
                      legend.var.title.txt = "Nombre de\nvotes exprimés", 
                      legend.var.pos = "topleft", 
                      var2 = 'shareLeave',
                      legend.var2.pos = "left", 
                      legend.var2.values.rnd = 0,
                      legend.var2.title.txt = "Part du vote\n'Leave' (en %)", 
                      breaks = bks,
                      col = cols)
plot(londonMask, lwd = 1, add=T)
layoutLayer(title = "Répartition et part du 'Leave' au référendum sur le brexit", 
            sources = "", author = "sources : ??? + GADM2.8", 
            theme = "blue.pal", scale = 100)
dev.off()

References

• official referendum vote results
• mapinsetr, faire un carton avec R
• Cartographier le vote pour le Brexit