Unfamiliar Maps

Many towns and cities share the same name. Some are less well known than others. Let’s take a look.

At least 3 people have booked flights to Sydney, Nova Scotia (population 30,000) intending to holiday in New South Wales (two orders of magnitude larger). There are a number of cases like this of towns and cities with larger and more well known doppelgangers. I thought it would be interesting to have a map that labelled the familiar names in the unfamiliar locations.

This is fairly easy to do in R, given the data that comes with the maps package. But bear in mind that the data is neither 100% accurate nor complete. Also, it was a mostly manual selection of what to include, based on my interpretations of what is interesting and well known. Feel free to make your own version, based on your knowledge and familiarity of the globe.

We can add labels to the map using the leaflet package. The cities are grouped by the continental region of the (main) familiar city.

Notes

• I left out Alexandria, Buenos Aires and San Francisco as there were so many alternatives.
• The labels on the map are a bit cluttered in places. Perhaps with more thought they could be handled better.
• Popups with more information (population etc) would be a nice improvement, but given that the data is outdated and unreliable I opted not to.
• The manually curated CSV file is available here.

Code listing

The R code to generate the map:

library(maps)
library(leaflet)
library(dplyr)
library(purrr)
data("world.cities")

# Manually prepared file giving name and region, and when ordered by population,
# how many of the largest are "familiar" and how many of the smallest are "unfamiliar"
my_cities <- readr::read_csv("data/familiar_cities.csv")

familiar <- 
  my_cities %>%
  inner_join(world.cities) %>% 
  group_by(name) %>% 
  mutate(rank_desc = rank(-pop)) %>% 
  filter(rank_desc <= num_familiar) %>% 
  ungroup() %>% 
  select(-num_familiar, -num_unfamiliar, -rank_desc)

unfamiliar <- 
  my_cities %>%
  inner_join(world.cities) %>% 
  group_by(name) %>% 
  mutate(rank_asc = rank(pop)) %>% 
  filter(rank_asc <= num_unfamiliar) %>% 
  ungroup() %>% 
  select(-num_familiar, -num_unfamiliar, -rank_asc)
leaflet(width = "100%") %>% 
  addProviderTiles("Esri.WorldGrayCanvas") %>% 
  addCircleMarkers(
    data = familiar %>% filter(region == "Americas"),
    group = "Americas - Familiar",
    radius = 6,
    stroke = FALSE,
    fillOpacity = 0.5,
    color = "red",
    label = ~name,
    labelOptions = labelOptions(noHide = T)) %>% 
  addCircleMarkers(
    data = unfamiliar %>% filter(region == "Americas"),
    group = "Americas - Unfamiliar",
    radius = 6,
    stroke = FALSE,
    fillOpacity = 0.5,
    color = "navy",
    options = markerOptions(riseOnHover = TRUE),
    label = ~name,
    labelOptions = labelOptions(noHide = T)) %>% 
  addCircleMarkers(
    data = familiar %>% filter(region == "Asia-Pacific"),
    group = "Asia/Pacific - Familiar",
    radius = 6,
    stroke = FALSE,
    fillOpacity = 0.5,
    color = "red",
    label = ~name,
    labelOptions = labelOptions(noHide = T)) %>% 
  addCircleMarkers(
    data = unfamiliar %>% filter(region == "Asia-Pacific"),
    group = "Asia/Pacific - Unfamiliar",
    radius = 6,
    stroke = FALSE,
    fillOpacity = 0.5,
    color = "navy",
    options = markerOptions(riseOnHover = TRUE),
    label = ~name,
    labelOptions = labelOptions(noHide = T)) %>% 
  addCircleMarkers(
    data = familiar %>% filter(region == "Europe-Africa"),
    group = "Europe/Africa - Familiar",
    radius = 6,
    stroke = FALSE,
    fillOpacity = 0.5,
    color = "red",
    label = ~name,
    labelOptions = labelOptions(noHide = T)) %>% 
  addCircleMarkers(
    data = unfamiliar %>% filter(region == "Europe-Africa"),
    group = "Europe/Africa - Unfamiliar",
    radius = 6,
    stroke = FALSE,
    fillOpacity = 0.5,
    color = "navy",
    options = markerOptions(riseOnHover = TRUE),
    label = ~name,
    labelOptions = labelOptions(noHide = T)) %>% 
  addLayersControl(
    overlayGroups = c("Americas - Familiar", "Americas - Unfamiliar",
                      "Asia/Pacific - Familiar", "Asia/Pacific - Unfamiliar",
                      "Europe/Africa - Familiar", "Europe/Africa - Unfamiliar"),
    options = layersControlOptions(collapsed = FALSE)) %>% 
  hideGroup("Americas - Familiar") %>%
  hideGroup("Asia/Pacific - Familiar") %>% 
  hideGroup("Europe/Africa - Familiar")