ggtern (version 3.5.0)

geom_smooth_tern: Add a Smoothed Conditional Mean.

Description

Aids the eye in seeing patterns in the presence of overplotting. geom_smooth_tern and stat_smooth_tern are effectively aliases: they both use the same arguments. Use geom_smooth_tern unless you want to display the results with a non-standard geom.

Usage

geom_smooth_tern(
  mapping = NULL,
  data = NULL,
  position = "identity",
  ...,
  method = "auto",
  formula = y ~ x,
  se = TRUE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  expand = c(0.5, 0.5)
)
stat_smooth_tern(
  mapping = NULL,
  data = NULL,
  position = "identity",
  ...,
  method = "auto",
  formula = y ~ x,
  se = TRUE,
  n = 80,
  span = 0.75,
  fullrange = FALSE,
  level = 0.95,
  method.args = list(),
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  expand = c(0.5, 0.5)
)

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

Position adjustment, either as a string naming the adjustment (e.g. "jitter" to use position_jitter), or the result of a call to a position adjustment function. Use the latter if you need to change the settings of the adjustment.

...

Other arguments passed on to layer(). These are often aesthetics, used to set an aesthetic to a fixed value, like colour = "red" or size = 3. They may also be parameters to the paired geom/stat.

method

Smoothing method (function) to use, accepts either NULL or a character vector, e.g. "lm", "glm", "gam", "loess" or a function, e.g. MASS::rlm or mgcv::gam, stats::lm, or stats::loess. "auto" is also accepted for backwards compatibility. It is equivalent to NULL.

For method = NULL the smoothing method is chosen based on the size of the largest group (across all panels). stats::loess() is used for less than 1,000 observations; otherwise mgcv::gam() is used with formula = y ~ s(x, bs = "cs") with method = "REML". Somewhat anecdotally, loess gives a better appearance, but is \(O(N^{2})\) in memory, so does not work for larger datasets.

If you have fewer than 1,000 observations but want to use the same gam() model that method = NULL would use, then set method = "gam", formula = y ~ s(x, bs = "cs").

formula

Formula to use in smoothing function, eg. y ~ x, y ~ poly(x, 2), y ~ log(x). NULL by default, in which case method = NULL implies formula = y ~ x when there are fewer than 1,000 observations and formula = y ~ s(x, bs = "cs") otherwise.

se

Display confidence interval around smooth? (TRUE by default, see level to control.)

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().

expand

expand the range of values by this much (vector of length 2) when fullrange is set to TRUE

n

Number of points at which to evaluate smoother.

span

Controls the amount of smoothing for the default loess smoother. Smaller numbers produce wigglier lines, larger numbers produce smoother lines. Only used with loess, i.e. when method = "loess", or when method = NULL (the default) and there are fewer than 1,000 observations.

fullrange

If TRUE, the smoothing line gets expanded to the range of the plot, potentially beyond the data. This does not extend the line into any additional padding created by expansion.

level

Level of confidence interval to use (0.95 by default).

method.args

List of additional arguments passed on to the modelling function defined by method.

Author

Nicholas Hamilton

Examples

data(Feldspar)
ggtern(data=Feldspar,aes(Ab,An,Or,group=Feldspar)) +  
  geom_smooth_tern(method=lm,fullrange=TRUE,colour='red') + 
  geom_point() +
  labs(title="Example Smoothing")