Combining Colors and Patterns

Experimental. The functions described here, scale_cheysson() and aes_cheysson(), are new in ggCheysson 1.1.0, and their interface may change in a future version.

library(ggCheysson)
library(ggplot2)
library(ggpattern)

Palettes that combine color and hatching

In the Albums de Statistique Graphique, a class on a map or a bar in a chart was rarely distinguished by color alone. Cheysson’s palettes combine colors with hatching: solid fills, stripes at different angles and spacings, and crosshatching, sometimes in two colors.

Each element of a palette in cheysson_patterns is therefore a small bundle of properties. Here are the six elements of palette 1886_28:

pats <- cheysson_pattern("1886_28")
data.frame(
  pattern       = cheysson_pattern_params(pats, "pattern_type"),
  fill          = cheysson_pattern_params(pats, "fill"),
  pattern_fill  = cheysson_pattern_params(pats, "pattern_fill"),
  pattern_fill2 = cheysson_pattern_params(pats, "pattern_fill2"),
  pattern_angle = cheysson_pattern_params(pats, "pattern_angle")
)
#>   pattern        fill pattern_fill pattern_fill2 pattern_angle
#> 1  stripe transparent      #d61d21       #d61d21            90
#> 2  stripe transparent      #53679b       #53679b             0
#> 3  stripe transparent      #060304       #060304             0
#> 4    none     #53679b      #53679b       #53679b            45
#> 5    none     #d61d21      #d61d21       #d61d21            45
#> 6    none     #060304      #060304       #060304            45

pattern: the hatch type, "none" for a solid fill
fill: the paper or fill color behind the hatching ("transparent" for hatching on bare paper)
pattern_fill: the color of the hatch lines
pattern_fill2: the color of a crosshatch’s second set of lines (the same as pattern_fill except in two-color crosshatches)
pattern_angle: the angle of the lines

The long way: one mapping and one scale per property

In ggplot2 with ggpattern, each of these properties is a separate aesthetic. To apply a palette to a variable, each aesthetic needs both a mapping in aes() and a scale that supplies its values:

trade <- data.frame(
  country = c("France", "England", "Germany", "Italy"),
  exports = c(2350, 3120, 2680, 1890)
)

ggplot(trade, aes(country, exports)) +
  geom_col_pattern(
    aes(fill = country, pattern = country, pattern_fill = country,
        pattern_fill2 = country, pattern_angle = country),
    pattern_colour = NA, pattern_density = 0.3, pattern_spacing = 0.025,
    colour = "black"
  ) +
  scale_fill_cheysson_pattern("1886_28") +
  scale_pattern_type_cheysson("1886_28") +
  scale_pattern_fill_cheysson("1886_28") +
  scale_pattern_fill2_cheysson("1886_28") +
  scale_pattern_angle_cheysson("1886_28") +
  labs(title = "Exports by Nation, 1885", x = NULL, y = "Thousands of francs") +
  theme_cheysson() +
  theme(legend.position = "none")

The short way: `aes_cheysson()` and `scale_cheysson()`

Two functions collapse the five mappings and the five scales to one line each:

aes_cheysson(country) maps country to all five aesthetics. Other mappings can be given as further arguments, e.g. aes_cheysson(country, x = year, y = value).
scale_cheysson("1886_28") returns the five scales as a list, which + adds to the plot in one step. All of them take their values from the same palette elements, so each level of country gets one complete historical swatch.

This draws the same plot as above:

ggplot(trade, aes(country, exports)) +
  geom_col_pattern(
    aes_cheysson(country),
    pattern_colour = NA, pattern_density = 0.3, pattern_spacing = 0.025,
    colour = "black"
  ) +
  scale_cheysson("1886_28") +
  labs(title = "Exports by Nation, 1885", x = NULL, y = "Thousands of francs") +
  theme_cheysson() +
  theme(legend.position = "none")

Settings that are better fixed than mapped stay in the geom: pattern_density and pattern_spacing (how thick and how close the lines are), pattern_colour = NA (no outlines around the hatch lines), and the outline colour.

Why both are needed

A scale does nothing for an aesthetic the plot doesn’t map. Here only fill and pattern are mapped, so scale_cheysson()’s other scales have no effect, and ggpattern falls back to its default grey hatch lines and angle:

ggplot(trade, aes(country, exports, fill = country, pattern = country)) +
  geom_col_pattern(pattern_colour = NA, pattern_density = 0.3, pattern_spacing = 0.025,
                   colour = "black") +
  scale_cheysson("1886_28") +
  labs(title = "Only fill and pattern mapped", x = NULL, y = "Thousands of francs") +
  theme_cheysson() +
  theme(legend.position = "none")

Legends

Arguments to scale_cheysson() such as name and labels are passed to every scale. With the same title, ggplot2 merges the legends of all the aesthetics into one, whose keys show the full swatches. Here a sequential palette, 1881_12, whose three steps are hatchings of increasing density in a single color, distinguishes three kinds of transport:

infrastructure <- data.frame(
  region = rep(c("North", "South", "East", "West"), each = 3),
  type   = factor(rep(c("Road", "Canal", "Rail"), 4), levels = c("Road", "Canal", "Rail")),
  length = c(250, 300, 450,  250, 400, 350,  300, 200, 500,  250, 350, 400)
)

ggplot(infrastructure, aes(region, length)) +
  geom_col_pattern(
    aes_cheysson(type),
    position = "dodge",
    pattern_colour = NA, pattern_density = 0.35, pattern_spacing = 0.02,
    colour = "black"
  ) +
  scale_cheysson("1881_12", name = "Network") +
  labs(title = "Transportation Networks by Region", x = NULL, y = "Hundreds of km") +
  theme_cheysson()

Ordered data: sequential and diverging palettes

Sequential palettes are stored from low to high (light to dark), and diverging palettes from one extreme through the middle to the other, so reverse = TRUE flips every palette the same way. When the data have fewer levels than the palette has elements, the scales pick elements spread over the whole palette, keeping both ends.

Palette 1883_31 is diverging: two hues, each used solid and hatched. As in Cheysson’s maps, the solid fills mark the extremes and the hatched versions the milder classes:

opinion <- data.frame(
  response = factor(c("Strongly against", "Against", "For", "Strongly for"),
                    levels = c("Strongly against", "Against", "For", "Strongly for")),
  percent = c(18, 27, 34, 21)
)

ggplot(opinion, aes(response, percent)) +
  geom_col_pattern(
    aes_cheysson(response),
    pattern_colour = NA, pattern_density = 0.35, pattern_spacing = 0.025,
    colour = "black"
  ) +
  scale_cheysson("1883_31") +
  labs(title = "A Diverging Palette", x = NULL, y = "Percent") +
  theme_cheysson() +
  theme(legend.position = "none")

Missing values

Missing values get no hatching and a plain fill, set by na.value (default "grey80"):

trade_na <- rbind(trade, data.frame(country = NA, exports = 1500))

ggplot(trade_na, aes(country, exports)) +
  geom_col_pattern(
    aes_cheysson(country),
    pattern_colour = NA, pattern_density = 0.3, pattern_spacing = 0.025,
    colour = "black"
  ) +
  scale_cheysson("1886_28", na.value = "grey90") +
  labs(title = "Exports by Nation, 1885", x = NULL, y = "Thousands of francs") +
  theme_cheysson() +
  theme(legend.position = "none")

Applying only some aesthetics

To use only some of the palette’s properties, choose them with aesthetics, and map only those. Here the bars keep the palette’s hatch types and line colors, but not its angles:

ggplot(trade, aes(country, exports, fill = country, pattern = country,
                  pattern_fill = country)) +
  geom_col_pattern(pattern_colour = NA, pattern_density = 0.3, pattern_spacing = 0.025,
                   colour = "black") +
  scale_cheysson("1886_28", aesthetics = c("fill", "pattern", "pattern_fill")) +
  labs(title = "Without the palette's angles", x = NULL, y = "Thousands of francs") +
  theme_cheysson() +
  theme(legend.position = "none")

The individual scales, scale_fill_cheysson_pattern() and the scale_pattern_*_cheysson() family, remain available for full control over each aesthetic.

What is not included

pattern_density and pattern_spacing are not mapped by aes_cheysson() or set by scale_cheysson(). The palettes’ spacings were measured on Cheysson’s small swatches and need rescaling for a full-size plot; see the literacy map in vignette("guerry-maps", package = "ggCheysson") for mapping pattern_spacing with scale_pattern_spacing_manual().
The scales are discrete. For continuous data, cut it into classes first, as Cheysson did.
For plots without patterns (geom_col(), geom_point(), …), use scale_fill_cheysson() and scale_color_cheysson(), which use the palettes’ colors only.

Michael Friendly

2026-10-01

Palettes that combine color and hatching

The long way: one mapping and one scale per property

The short way: `aes_cheysson()` and `scale_cheysson()`

Why both are needed

Legends

Ordered data: sequential and diverging palettes

Missing values

Applying only some aesthetics

What is not included

Combining Colors and Patterns

Michael Friendly

2026-10-01

Palettes that combine color and hatching

The long way: one mapping and one scale per property

The short way: aes_cheysson() and scale_cheysson()

Why both are needed

Legends

Ordered data: sequential and diverging palettes

Missing values

Applying only some aesthetics

What is not included

The short way: `aes_cheysson()` and `scale_cheysson()`