On message and on brand: conversation-starting dataviz with R and ggplot2

Workshop for the MaineR User Group in which we explored questions we should ask ourselves to make sure our visualisation are on message, and tricks we can use to make sure any future graph we build is on brand

Written by

Affiliation

Cara Thompson

Building Stories with Data

Recording

Coming soon!

Slides

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Full code

library(ggplot2)

penguins <- penguins |>
  dplyr::filter(!is.na(sex))


penguin_colours <- c(
  "Chinstrap" = "#F2B5CD",
  "Adelie" = "#F7A115",
  "Gentoo" = "#356B40"
)


theme_maineR <- function(base_text_size = 20) {
  theme_minimal(base_size = base_text_size) +
    theme(
      text = element_text(family = "Source Sans 3", colour = "#343a40"),
      geom = element_geom(
        family = "Source Sans 3",
        ink = "#343a40",
        pointshape = 21,
        pointsize = 5,
        linewidth = 0.5,
        fill = "#4e226f"
      ),
      axis.title = element_blank(),
      legend.position = "top",
      legend.title = element_blank(),
      strip.background = element_rect(fill = "#4e226f"),
      strip.text = element_text(colour = "white", face = "bold"),
      panel.background = element_rect(colour = "#b17ed8", fill = "#FBF8FD"),
      plot.background = element_rect(fill = "#FBF8FD", colour = "#FBF8FD"),
      panel.grid = element_line(colour = "white"),
      plot.title.position = "plot",
      plot.title = ggtext::element_textbox_simple(
        size = rel(1.6),
        colour = "#4e226f",
        face = "bold",
        margin = margin(0, 0, base_text_size / 2, 0)
      ),
      plot.subtitle = ggtext::element_textbox_simple(
        size = rel(1.2),
        margin = margin(0, 0, base_text_size, 0),
        lineheight = 1.3
      ),
      plot.margin = margin_auto(base_text_size * 1.5)
    )
}

penguins |>
  ggplot() +
  annotate(
    "rect",
    xmin = 50,
    xmax = Inf,
    ymin = -Inf,
    ymax = Inf,
    fill = alpha("red", 0.1)
  ) +
  geom_text(
    data = penguins |> dplyr::filter(island == "Biscoe") |> head(1),
    aes(x = 50, y = I(0.925), label = "Beaks > 50mm 😱"),
    hjust = -0.1
  ) +
  geom_vline(xintercept = 50, colour = "red") +
  geom_point(
    aes(x = bill_len, y = sex, fill = species, size = body_mass),
    position = ggbeeswarm::position_quasirandom(width = 0.2),
    shape = 21,
    colour = "#2c3d4f"
  ) +
  scale_fill_manual(
    values = penguin_colours
  ) +
  scale_y_discrete(labels = function(x) stringr::str_to_sentence(x)) +
  scale_x_continuous(limits = c(25, NA), labels = function(x) paste0(x, "mm")) +
  scale_size(labels = scales::label_comma(suffix = "g")) +
  labs(
    title = "Biscoe is your best bet",
    subtitle = "Stick to the female Gentoos, and hopefully you'll manage to avoid the outlier!"
  ) +
  facet_grid("island") +
  guides(
    fill = guide_legend(override.aes = list(size = 5))
  ) +
  theme_maineR(base_text_size = 12)

Resources I mentioned

• Check colours are different from each other: vis4.net/palettes
• Check colours are distinct enough from their background: colourcontrast.cc
• Blend colours together for a more cohesive and accessible palette: monochromeR

Happy datavizing!