Beautiful Maps with R (III): Patterns and hatched maps

Updated 17 february 2020: All these pieces of work are already available on cartography >v.2.4.0 on functions hatchedLayer and legendHatched. Just install it via install.packages("cartography"). A dedicated blog post with examples on this link.

On this post I would show how to produce different filling patterns that could be added over your shapefiles with the cartography package.

Required R packages

library(sf)
library(dplyr)
library(giscoR)
library(cartography)

DE <- gisco_get_countries(country = "Germany", epsg = 3857)

Let’s see how it works.

par(
  mfrow = c(3, 4),
  mar = c(1, 1, 1, 1),
  cex = 0.5
)
hatchedLayer(DE, "dot")
title("dot")
hatchedLayer(DE, "text", txt = "Y")
title("text")
hatchedLayer(DE, "diamond", density = 0.5)
title("diamond")
hatchedLayer(DE, "grid", lwd = 1.5)
title("grid")
hatchedLayer(DE, "hexagon", col = "blue")
title("hexagon")
hatchedLayer(DE, "horizontal", lty = 5)
title("horizontal")
hatchedLayer(DE, "vertical")
title("vertical")
hatchedLayer(DE, "left2right")
title("left2right")
hatchedLayer(DE, "right2left")
title("right2left")
hatchedLayer(DE, "zigzag")
title("zigzag")
hatchedLayer(DE, "circle")
title("circle")

plot of chunk 20191212_showfun

Let’s play a little bit more with some of the additional features of the function:

par(mar = c(1, 1, 1, 1), mfrow = c(2, 3))
plot(st_geometry(DE))
hatchedLayer(
  DE,
  "dot",
  pch = 10,
  density = 0.5,
  cex = 2,
  col = "darkblue",
  add = T
)
plot(st_geometry(DE))
hatchedLayer(
  DE,
  "dot",
  pch = 21,
  col = "red",
  bg = "green",
  cex = 1.25,
  add = T
)
plot(st_geometry(DE), col = "grey")
hatchedLayer(
  DE,
  "text",
  txt = "DE",
  density = 1.1,
  col = "white",
  add = T
)
plot(st_geometry(DE), col = "blue")
hatchedLayer(
  DE,
  "horizontal",
  lty = 3,
  cellsize = 150 * 1000,
  add = T
)
hatchedLayer(DE, "zigzag", lwd = 2, col = "red")
plot(st_geometry(DE), border = "orange", lwd = 2)
hatchedLayer(DE,
  "left2right",
  density = 2,
  col = "orange",
  add = T
)

plot of chunk 20191212_playing

Adding legends: the `legendHatched` function

As a complementary function, there is also the legendHatched. Main parameters are:

pos, title.txt, title.cex, values.cex,categ, cex and frame: See ?cartography::legendTypo.
patterns: vector of patterns to be created for each element on categ.
ptrn.bg: Background of the legend box for each categ.
ptrn.text: Text to be used for each categ="text", as a single value or a vector.
dot.cex: cex of each categ="dot", as a single value or a vector.
text.cex: text size of each categ="text", as a single value or a vector.
As in the case of the hatchedLayerfunction, different graphical parameters can be passed (lty, lwd, pch, bg on points).

Note that is also possible to create solid legends, by setting col and ptrn.bg to the same color. Parameters would respect the order of the categ variable.

par(mar = c(0, 0, 0, 0), mfrow = c(1, 1))
plot(st_geometry(DE)) # Null geometry
legendHatched(
  title.txt = "Example 1",
  categ = c("a", "b"),
  patterns = "dot",
  pch = c(16, 23),
  frame = T
)
legendHatched(
  pos = "left",
  title.txt = "Example 2",
  categ = c("c", "d", "other text"),
  patterns = c("text", "zigzag"),
  ptrn.text = c("s", "pp"),
  ptrn.bg = "grey80",
  col = c("red", "blue")
)

legendHatched(
  pos = "topright",
  title.txt = "Example 3",
  categ = c("e", "f", "solid"),
  patterns = c("circle", "left2right"),
  ptrn.bg = c("orange", "yellow", "green"),
  col = c("white", "white", "green"),
  lty = c(2, 4),
  lwd = c(1, 3)
)


legendHatched(
  pos = "bottomright",
  title.txt = "Example 4",
  values.cex = 1.2,
  categ = c("h", "i", "j", "k"),
  patterns = c("grid", "diamond", "horizontal", "dot"),
  cex = 2,
  pch = 22,
  col = "white",
  ptrn.bg = "black",
  bg = "pink"
)

plot of chunk 20191212_playinglegend

I hope that you find this functions useful. Enjoy and nice mapping!

plot of chunk 20191212_imgpost

Required R packages

Adding legends: the legendHatched function

Adding legends: the `legendHatched` function