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Add an 'hourglass' layer to a ggplot

Source: R/geom_hourglass.R
geom_hourglass.Rd

geom_hourglass() takes a continuous datetime object, splits in in discrete dates and time of day with stat_hourglass(). This geometry is a wrapper to add it as a layer to a ggplot. GeomHourglass is a ggproto object inheriting from ?ggplot2::GeomPoint. It should not be used directly. Instead call geom_hourglass().

Usage

GeomHourglass

geom_hourglass(
  mapping = NULL,
  data = NULL,
  stat = "hourglass",
  position = "identity",
  na.rm = FALSE,
  show.legend = NA,
  hour_center = 0,
  inherit.aes = TRUE,
  ...
)

Format

An object of class GeomHourglass (inherits from GeomPoint, Geom, ggproto, gg) of length 3.

Arguments

mapping

Set of aesthetic mappings created by ggplot2::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. The hourglass stat and geom requires either the x axis or the y axis to be mapped. The mapped aesthetic will show the date of the variable, whereas the opposite axis will show the time of day.

data

The data to be displayed in this layer. If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot2::ggplot(). Otherwise, a data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See ggplot2::fortify() for which variables will be created. The data should contain a column with datetime values (e.g., ?POSIXct)

stat

Can be used to overwrite the default connection between geom_hourglass and stat_hourglass().

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.

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.

hour_center

The hour at which the time of day is centred. Default is 0, meaning midnight. -12 centres around noon of the preceding day, +12 centres around noon of the next day.

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().

...

Arguments passed to geometry.

Value

Returns a ggplot2::layer() which can be added to a ggplot2::ggplot()

Author

Pepijn de Vries

Examples

library(ggplot2)
data(bats)

monitoring <- attr(bats, "monitoring")

ggplot(subset(bats, format(RECDATETIME, "%Y") == "2019"),
       aes(x = RECDATETIME, col = SPECDESCSCI)) +
  geom_hourglass()


ggplot(dplyr::mutate(bats, YEAR = format(RECDATETIME, "%Y")),
       aes(x = RECDATETIME, col = SPECDESCSCI)) +
  geom_hourglass() +
  facet_wrap(~YEAR, scales = "free_x")