Figure 3.9 Equal area world in a square

figures

code

This equal-area projection could replace Web Mercator as the top level global web tile ‘world in a square’.

With astonishing foresight, it was proposed for that purpose in this paper in 1986:

Tobler WR and ZT Chen. 1986. A quadtree for global information storage. Geographical Analysis 18(4) 360–371. doi: 10.1111/j.1538-4632.1986.tb00108.x.

Given the upset that accompanied the Gall-Peters projection, another ‘odd-looking’ equal-area projection (only ‘odd’ because people are so accustomed to Mercator), it’s not clear it would catch on! See this paper for a discussion of that controversy:

Crampton, J. 1994. Cartography’s defining moment: the Peters projection controversy, 1974–1990. Cartographica 31(4) 16–32. doi: 10.3138/1821-6811-L372-345P.

In any case, this is simply a standard cylindrical equal-area projection with standard parallels chosen to make the whole map area square.

Code

library(sf)
library(tmap) # for its world dataset
library(ggplot2)
library(tmaptools)
library(dplyr)

Set up some theme stuff for the maps.

Code

theme_set(theme_void())
theme_update(
  plot.margin = unit(c(0, 0, 0, 0), "pt"),
  plot.background = element_rect(fill = "#ddeeff"),
  panel.background = element_rect(fill = NA),
  panel.border = element_rect(fill = NA, linewidth = 0.5),
  panel.grid = element_line(colour = "black", linewidth = 0.05),
  panel.ontop = TRUE
)

Use the supplied World dataset (in lat-lon EPSG 4326) and project as required!

Code

data("World") 
world_tc <- World |>
  select(geometry) |>
  st_transform("+proj=cea lat_ts=55.654")

ggplot(world_tc) +
  geom_sf(fill = "#aaeecc", colour = NA) +
  coord_sf(label_graticule = "", expand = FALSE) +
  scale_x_continuous(breaks = -12:12 * 15) +
  scale_y_continuous(breaks = -6:6 * 15)

Code

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