Skip to contents

Hexagonal heatmap of 2d bin summaries sized by bin counts

Source: R/GeomHextile.R, R/geom_hextile.R
geom_hextile.Rd

Divides the plane into regular hexagons, counts the number of cases in each hexagon, and then (by default) maps the number of cases to the hexagon size and fill. If a z aesthetic is provided, the hexagon fill is instead mapped to the summary of z with fun. z2 and z3 are made available in the case that multiple summary statistics are required. Hexagon bins avoid the visual artefacts sometimes generated by the very regular alignment of ggplot2::geom_bin_2d().

Usage

geom_hextile(
  mapping = NULL,
  data = NULL,
  stat = "summary_hextile",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

stat_summary_hextile(
  mapping = NULL,
  data = NULL,
  geom = "hextile",
  position = "identity",
  ...,
  bins = 30,
  binwidth = NULL,
  drop = TRUE,
  fun = "mean",
  fun.args = list(),
  fun2 = "mean",
  fun2.args = list(),
  fun3 = "mean",
  fun3.args = list(),
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

position

A position adjustment to use on the data for this layer. This can be used in various ways, including to prevent overplotting and improving the display. The position argument accepts the following:

  • The result of calling a position function, such as position_jitter(). This method allows for passing extra arguments to the position.

  • A string naming the position adjustment. To give the position as a string, strip the function name of the position_ prefix. For example, to use position_jitter(), give the position as "jitter".

  • For more information and other ways to specify the position, see the layer position documentation.

...

Other arguments passed on to layer()'s params argument. These arguments broadly fall into one of 4 categories below. Notably, further arguments to the position argument, or aesthetics that are required can not be passed through .... Unknown arguments that are not part of the 4 categories below are ignored.

  • Static aesthetics that are not mapped to a scale, but are at a fixed value and apply to the layer as a whole. For example, colour = "red" or linewidth = 3. The geom's documentation has an Aesthetics section that lists the available options. The 'required' aesthetics cannot be passed on to the params. Please note that while passing unmapped aesthetics as vectors is technically possible, the order and required length is not guaranteed to be parallel to the input data.

  • When constructing a layer using a stat_*() function, the ... argument can be used to pass on parameters to the geom part of the layer. An example of this is stat_density(geom = "area", outline.type = "both"). The geom's documentation lists which parameters it can accept.

  • Inversely, when constructing a layer using a geom_*() function, the ... argument can be used to pass on parameters to the stat part of the layer. An example of this is geom_area(stat = "density", adjust = 0.5). The stat's documentation lists which parameters it can accept.

  • The key_glyph argument of layer() may also be passed on through .... This can be one of the functions described as key glyphs, to change the display of the layer in the legend.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders().

geom, stat

geom,stat Override the default connection between geom_hextile() and stat_summary_hextile(). For more information about overriding these connections, see how the stat and geom arguments work.

bins

numeric vector giving number of bins in both vertical and horizontal directions. Set to 30 by default.

binwidth

Numeric vector giving bin width in both vertical and horizontal directions. Overrides bins if both set.

drop

drop if the output of fun is NA.

fun, fun2, fun3

function for summary.

fun.args, fun2.args, fun3.args

A list of extra arguments to pass to fun

Value

A ggplot2::layer()]

Aesthetics

geom_hextile() understands the following aesthetics. Required aesthetics are displayed in bold and defaults are displayed for optional aesthetics:

Learn more about setting these aesthetics in vignette("ggplot2-specs").

stat_summary_hextile() understands the following aesthetics. Required aesthetics are displayed in bold and defaults are displayed for optional aesthetics:

  • x: horizontal position

  • y: vertical position

  • z, z2, z3: value passed to each summary function

Learn more about setting these aesthetics in vignette("ggplot2-specs").

Computed variables

These are calculated by the 'stat' part of layers and can be accessed with delayed evaluation.

  • after_stat(x), after_stat(y)
    location.

  • after_stat(count)
    number of points in bin.

  • after_stat(density)
    density of points in bin, scaled to integrate to 1.

  • after_stat(ncount)
    count, scaled to maximum of 1.

  • after_stat(ndensity)
    density, scaled to maximum of 1.

  • after_stat(value)
    number of points in bin, or if z is supplied, value of summary statistic from z.

  • after_stat(value2)
    if z2 is supplied, value of summary statistic from z2.

  • after_stat(value3)
    if z3 is supplied, value of summary statistic from z3.

Controlling binning parameters for the x and y directions

The arguments bins and binwidth can be set separately for the x and y directions. When given as a scalar, one value applies to both directions. When given as a vector of length two, the first is applied to the x direction and the second to the y direction. Alternatively, these can be a named list containing x and y elements, for example list(x = 10, y = 20).

See also

scale_size_tile(), draw_key_hextile(), ggplot2::stat_summary_hex(), ggplot2::stat_bin_hex(), ggplot2::geom_hex().

Examples

library(ggplot2)

d <- ggplot(diamonds, aes(carat, depth, z = price))

# fill: median price in bin
# size: number of points in bin
d +
  geom_hextile(fun = "median") +
  scale_size_tile(limits = c(0, 100))


# fill: mean price in bin
# size: sum of prices in bin
d +
  geom_hextile(aes(z2 = price, size = after_stat(value2)), fun2 = "sum") +
  scale_size_tile(limits = c(0, 1e5))


# fill: mean price in bin
# size: density, scaled to maximum of 1, weighted by price
d +
  geom_hextile(aes(weight = price, size = after_stat(ndensity))) +
  scale_size_tile(limits = c(0, 0.1))


# fill: number of points in bin
# size: number of points in bin
ggplot(diamonds, aes(carat, depth)) +
  geom_hextile() +
  scale_size_tile(limits = c(0, 100))