README.md
In ggpointless: Additional Geometries and Stats for 'ggplot2'

ggpointless

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ggpointless is an extension of the ggplot2 library providing additional layers.

You can install ggpointless from CRAN with:

install.packages("ggpointless")

To install the development version from GitHub use:

# install.packages("devtools")
devtools::install_github("flrd/ggpointless")

Once you have installed the package, attach it by calling:

library(ggpointless)

geom_pointless() – emphasizes some observations with points
geom_lexis() – draws a Lexis diagram
geom_chaikin() – applies Chaikin’s corner cutting algorithm
geom_catenary() – draws a catenary curve

See vignette("ggpointless") for details and examples.

geom_pointless() let’s you highlight the first, or last observations, sample minimum and sample maximum to provide additional context. Or just some visual sugar. geom_pointless() behaves similar to geom_point() except that it has a location argument. You can set it to "first", "last" (default), "minimum", "maximum", and "all", where "all" is just shorthand to select "first", "last", "minimum" and "maximum".

cols <- c("#f4ae1b", "#d77e7b", "#a84dbd", "#311dfc")
theme_set(theme_minimal())

x <- seq(-pi, pi, length.out = 500)
y <- outer(x, 1:5, function(x, y) sin(x * y))

df1 <- data.frame(
  var1 = x,
  var2 = rowSums(y)
)

ggplot(df1, aes(x = var1, y = var2)) +
  geom_line() +
  geom_pointless(aes(color = after_stat(location)),
    location = "all",
    size = 3
  ) +
  scale_color_manual(values = cols)

geom_lexis() is a combination of a segment and a point layer. Given a start value and an end value, this function draws a 45° line which indicates the duration of an event. Required are x and xend aesthetics, y and yend coordinates will be calculated.

df2 <- data.frame(
  key = c("A", "B", "B", "C", "D"),
  x = c(0, 1, 6, 5, 6),
  xend = c(5, 4, 10, 8, 10)
)

ggplot(df2, aes(x = x, xend = xend, color = key)) +
  geom_lexis(aes(linetype = after_stat(type)), size = 2) +
  coord_equal() +
  scale_x_continuous(breaks = c(df2$x, df2$xend)) +
  scale_color_manual(values = cols) +
  scale_linetype_identity() +
  theme(panel.grid.minor = element_blank())

See also the LexisPlotR package.

Chaikin’s corner cutting algorithm let’s you turn a ragged path or polygon into a smoothed one. Credit to Farbfetzen / corner_cutting.

lst <- list(
  data = list(
    closed_square = data.frame(x = c(0, 0, 1, 1), y = c(2, 3, 3, 2)),
    whale = data.frame(x = c(.5, 4, 4, 3.5, 2), y = c(.5, 1, 1.5, .5, 3)),
    open_triangle = data.frame(x = c(3, 3, 5), y = c(2, 3, 3)),
    closed_triangle = data.frame(x = c(3.5, 5, 5), y = c(0, 0, 1.5))
  ),
  color = cols,
  closed = c(TRUE, TRUE, FALSE, TRUE)
)

ggplot(mapping = aes(x, y)) +
  lapply(lst$data, function(i) {
    geom_polygon(data = i, fill = NA, linetype = "12", color = "#777777")
  }) +
  Map(f = function(data, color, closed) {
    geom_chaikin(data = data, color = color, closed = closed)
  }, data = lst$data, color = lst$color, closed = lst$closed) +
  geom_point(data = data.frame(x = 1.5, y = 1.5)) +
  coord_equal()

See also the smoothr package.

Draws a flexible curve that simulates a chain or rope hanging loosely between two fixed points. By default, a chain length twice the Euclidean distance between each x/y combination is used. See vignette("ggpointless") for details.

Credit to: dulnan/catenary-curve

ggplot(data.frame(x = 1:5, y = sample(5)),
       aes(x, y)) + 
  geom_catenary() +
  geom_point(size = 3, colour = "#f4ae1b")
#> Set chainLength to 23.7