ireland_consituency_results_map.R

install.packages("needs")
library(needs)
needs(tidyverse, magrittr, rvest, sf, raster, rgdal)

ireland_constits <- c("https://en.wikipedia.org/wiki/Carlow%E2%80%93Kilkenny_(D%C3%A1il_constituency)") %>%
  read_html() %>%
  html_nodes('div[aria-labelledby="Current_Dáil_constituencies"] tr:nth-child(2) ul li a') %>%
  html_attr("href") %>%
  tail(-1) %>%
  c("/wiki/Carlow%E2%80%93Kilkenny_(D%C3%A1il_constituency)", .)

ireland_constit_results <- paste0("https://en.wikipedia.org", ireland_constits) %>%
  imap_dfr(~{
    read_html(.x) %>%
      html_nodes("table.wikitable") %>%
      map_dfr(~{
        council <- .x %>% html_node("th") %>% html_text() %>% str_replace_all("(2020 general election\\: )|\\[.+","")
        title <- .x %>% html_node("th a") %>% html_attr("title") %>% replace_na("foo")
        content <- .x
        if(title == "2020 Irish general election"){
          party <- content %>% html_nodes("td:nth-child(2)") %>% html_text(T)
          FPv <- content %>% html_nodes("td:nth-child(4)") %>% html_text(T) %>% parse_number()
          return(tibble(party, FPv) %>% mutate(council))
        }else{
          
        }
      }) %>%
      compact()
  })

unzip("~/Downloads/ne_10m_populated_places.zip", exdir = "~/Downloads/ireland_pop_dens/populated_places")
populated_places <- st_read("~/Downloads/ireland_pop_dens/populated_places/ne_10m_populated_places.shp")
populated_places_IRL <- populated_places %>%
  filter(ADM0NAME == "Ireland") %>%
  dplyr::select(NAME, NATSCALE, geometry, LONGITUDE, LATITUDE)

unzip("~/Downloads/ne_10m_admin_0_map_subunits.zip", exdir = "~/Downloads/GIS/world")
ireland_island_map <- st_read("~/Downloads/GIS/world/ne_10m_admin_0_map_subunits.shp") %>% st_transform(4326) %>% filter(GU_A3 %in% c("IRL", "NIR"))

# Ireland constituency shapefiles source: https://data.gov.ie/dataset/constituency-boundaries-ungeneralised-2017-osi-national-electoral-boundaries
unzip("~/Downloads/Constituency_Boundaries_Ungeneralised_2017__OSi_National_Electoral_Boundaries.zip", exdir = "~/Downloads/ireland_pop_dens/constituencies_2017")
ireland_constits_map <- st_read("~/Downloads/ireland_pop_dens/constituencies_2017/Constituency_Boundaries_Ungeneralised_2017__OSi_National_Electoral_Boundaries.shp") %>% st_transform(4326)
ireland_constits_map %>%
  dplyr::select(ENGLISH_NA, geometry) %>%
  mutate(council = as.character(ENGLISH_NA) %>% str_replace_all("\\s\\(.+", "") %>% str_replace_all("^D$", "Dún Laoghaire")) %>%
  left_join(
    ireland_constit_results %>%
      filter(party == "Sinn Féin") %>%
      group_by(party, council) %>%
      summarise(FPv = sum(FPv)) %>%
      ungroup() %>%
      mutate(council = council %>% str_replace_all("–","-"))
  ) %>%
  mutate(FPv = replace(FPv, is.na(FPv), 0)) -> ireland_constits_map_SF

ggplot() +
  theme_minimal() +
  theme(
    panel.grid.major = element_line(colour = 'transparent'),
    axis.text = element_blank(),
    axis.title = element_blank()
  ) +
  geom_sf(data=ireland_island_map, fill = "#CCCCCC", col = "transparent", size=0) +
  geom_sf(data=ireland_constits_map_SF, aes(fill = FPv), col = "transparent", size=0) +
  geom_sf(data=populated_places_IRL %>% filter(NATSCALE >= 0), col = "black") +
  geom_text(data=populated_places_IRL %>% filter(NATSCALE >= 0), aes(label = NAME, x = LONGITUDE, y = LATITUDE), col = "black", hjust=0) +
  scale_fill_gradientn(colours=c("#f2f2ee","#8d1a14"), limits=c(0,50), guide = guide_colorbar(ttile = "First preference votes (%)"))