stat_stratum: Stratum positions

Description

Given a dataset with alluvial structure, stat_stratum calculates the centroids of the strata at each axis, together with their weights (heights).

Usage

stat_stratum(mapping = NULL, data = NULL, geom = "stratum",
  position = "identity", decreasing = NA, reverse = TRUE,
  discern = FALSE, label.strata = FALSE, min.height = NULL,
  max.height = NULL, show.legend = NA, inherit.aes = TRUE,
  na.rm = FALSE, ...)

Arguments

mapping

Set of aesthetic mappings created by aes() or 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)).

geom

The geometric object to use display the data; override the default.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

decreasing

Logical; whether to arrange the strata at each axis in the order of the variable values (NA, the default), in ascending order of total weight (largest on top, FALSE), or in descending order of total weight (largest on bottom, TRUE).

reverse

Logical; if decreasing is NA, whether to arrange the strata at each axis in the reverse order of the variable values, so that they match the order of the values in the legend. Ignored if decreasing is not NA. Defaults to TRUE.

discern

Passed to to_lodes_form() if data is in alluvia format.

label.strata

Logical; whether to assign the values of the axis variables to the strata. Defaults to FALSE, and requires that no label aesthetic is assigned.

min.height, max.height

Numeric; bounds on the heights (weights) of the strata to be rendered. Use these bounds to exclude strata outside a certain range, for example when labeling strata using ggplot2::geom_text().

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().

na.rm

Logical: if FALSE, the default, NA lodes are not included; if TRUE, NA lodes constitute a separate category, plotted in grey (regardless of the color scheme).

...

Additional arguments passed to ggplot2::layer().

Aesthetics

stat_alluvium, stat_flow, and stat_stratum require one of two sets of aesthetics:

x and at least one of alluvium and stratum
any number of axis[0-9]* (axis1, axis2, etc.)

Use x, alluvium, and/or stratum for data in lodes format and axis[0-9]* for data in alluvia format (see alluvial-data). Arguments to parameters inconsistent with the format will be ignored. Additionally, each stat_* layer accepts the following optional aesthetics:

y
group

y controls the heights of the alluvia and may be aggregated across equivalent observations. group is used internally; arguments are ignored. Finally, stat_stratum accepts the following optional aesthetic:

label

label is used to label the strata and must take a unique value across the observations within each stratum. These and any other aesthetics are aggregated as follows: Numeric aesthetics, including y, are summed. Character and factor aesthetics, including label, are assigned to strata provided they take unique values across the observations within each stratum (otherwise NA is assigned).

Examples

Run this code

# NOT RUN {
# only `stratum` assignment is necessary to generate strata
data(vaccinations)
ggplot(vaccinations,
       aes(y = freq,
           x = survey, stratum = response,
           fill = response)) +
  stat_stratum(width = .5)

# lode data: positioning with weight labels
ggplot(vaccinations,
       aes(y = freq,
           x = survey, stratum = response, alluvium = subject,
           label = freq)) +
  stat_stratum(geom = "errorbar") +
  geom_text(stat = "stratum")
# lode data: positioning with stratum labels
ggplot(vaccinations,
       aes(y = freq,
           x = survey, stratum = response, alluvium = subject,
           label = response)) +
  stat_stratum(geom = "errorbar") +
  geom_text(stat = "stratum")

# alluvium data: positioning with weight labels
ggplot(as.data.frame(Titanic),
       aes(y = Freq,
           axis1 = Class, axis2 = Sex, axis3 = Age, axis4 = Survived,
           label = Freq)) +
  geom_text(stat = "stratum") +
  stat_stratum(geom = "errorbar") +
  scale_x_discrete(limits = c("Class", "Sex", "Age", "Survived"))
# alluvium data: positioning with stratum labels
ggplot(as.data.frame(Titanic),
       aes(y = Freq,
           axis1 = Class, axis2 = Sex, axis3 = Age, axis4 = Survived)) +
  geom_text(stat = "stratum", label.strata = TRUE) +
  stat_stratum(geom = "errorbar") +
  scale_x_discrete(limits = c("Class", "Sex", "Age", "Survived"))

# omit labels for strata outside a weight range
ggplot(vaccinations,
       aes(y = freq,
           x = survey, stratum = response,
           fill = response, label = response)) +
  stat_stratum(width = .5) +
  geom_text(stat = "stratum", min.height = 100)
# }

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