1  Points

Code and charts for the 2022 30-Day Map Challenge

This is pretty much a non-interactive version of a chart from the 2022 30-Day Chart Challenge, since I’m trying not to spend too much time on this and also had to set up the book today.

Setup

library(tidyverse)     # for data wrangling
library(sf)            # for maps
library(rnaturalearth) # for map coordinates
library(ggthemes)      # for the map theme
library(showtext)      # for fonts

# install a good Scottish font
# https://www.fontspace.com/hill-house-font-f40002
font_add(family = "Hill House",
         regular = "fonts/Hill_House.otf")
showtext_auto()

1.1 Data

The Database of British and Irish Hills v17.3 has a table of the Munros, with columns for many years (I guess which hills are classified as Munros changes over time). Let’s get just the current munros and fix some of the names.

Code

munros <- read_csv("data/munrotab_v8.0.1.csv",
                   show_col_types = FALSE) %>%
  filter(`2021` == "MUN") %>%
  select(-c(`1891`:`2021`)) %>% # get rid of the year columns
  rename(height_m = "Height (m)", 
         height_ft = "Height\n(ft)")

Make a quick histogram of their heights to get an overview of the data. I’d usually use the metric system, but since Munros are defined as hills over 3000 feet, I’ll use feet.

Code

ggplot(munros, aes(x = height_ft)) +
  geom_histogram(binwidth = 100, boundary = 0, 
                 color = "black", fill = "white")

1.2 Map of Scotland

Now I need a map of Scotland.

Code

scotland_sf <- ne_states(geounit = "Scotland", 
                         returnclass = "sf")

The munro table locates the peaks using grid coordinates, and the map uses latitude and longitude. So I translated the grid coordinates to latitude and longitude using Stackoverflow code from hrbrmstr.

Code

latlon <- map2(munros$xcoord, munros$ycoord, os.grid.to.lat.lon)

munros$lat <- map_dbl(latlon, `[[`, 1)
munros$lon <- map_dbl(latlon, `[[`, 2)

Then plot the latitude and longitude coordinates on the map, colored by height.

Code

ggplot() + 
  geom_sf(data = scotland_sf,
          mapping = aes(),
          color = "black", 
          fill = "grey",
          size = .1) +
  coord_sf(xlim = c(-8, 0), ylim = c(54, 61)) +
  geom_point(aes(x = lon, y = lat, color = height_ft), munros) +
  theme_map()

1.3 Make it prettier

There’s no munros on the Northern Isles, so I’ve cropped them out of the map. I also made the colours better. I added a label to geom_point(), which will produce a warning that it isn’t used, but you’ll see why in the next step.

The version of Hill House I have doesn’t have lowercase letters, so I’m using all uppercase for the title.

Code

munro_plot <- ggplot() + 
  geom_sf(data = scotland_sf,
          mapping = aes(),
          color = "chocolate4", 
          fill = "tan",
          size = .1) +
  coord_sf(xlim = c(-7.4, -2), ylim = c(54.8, 58.5)) +
  geom_point(aes(label = Name, color = height_ft, y = lat, x = lon), 
             data = arrange(munros, height_ft),
             size = 0.5) +
  scale_color_viridis_c(name = "Height (ft)",
                        limits = c(3000, 4500)) +
  labs(x = NULL, y = NULL,
       title = "THE MUNROS OF SCOTLAND",
       caption = "Data from The Database of British and Irish Hills | Plot by @debruine@tech.lgbt") +
  theme_map() +
  theme(legend.position = c(0, 0),
        legend.background = element_blank(),
        panel.background = element_rect(fill = "transparent", color = "transparent"),
        plot.background = element_rect(fill = "lightskyblue1", color = "transparent"),
        plot.title = element_text(family = "Hill House", size = 26, hjust = .5)
  )

munro_plot

The location and height of Scotland’s Munros.