The method for calculating the ellipses has been modified from
car::ellipse (Fox and Weisberg, 2011)
stat_ellipse(mapping = NULL, data = NULL, geom = "path", position = "identity", ..., type = "t", level = 0.95, segments = 51, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)
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.
The data to be displayed in this layer. There are three options:
NULL, the default, the data is inherited from the plot
data as specified in the call to
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.
function will be called with a single argument,
the plot data. The return value must be a
will be used as the layer data.
The geometric object to use display the data
Position adjustment, either as a string, or the result of a call to a position adjustment function.
other arguments passed on to
layer. These are
often aesthetics, used to set an aesthetic to a fixed value, like
color = "red" or
size = 3. They may also be parameters
to the paired geom/stat.
The type of ellipse.
"t" assumes a multivariate t-distribution, and
"norm" assumes a multivariate normal distribution.
"euclid" draws a circle with the radius equal to
representing the euclidean distance from the center.
This ellipse probably won't appear circular unless
coord_fixed() is applied.
The confidence level at which to draw an ellipse (default is 0.95),
type="euclid", the radius of the circle to be drawn.
The number of segments to be used in drawing the ellipse.
FALSE, the default, missing values are removed with
a warning. If
TRUE, missing values are silently removed.
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.
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.
John Fox and Sanford Weisberg (2011). An R Companion to Applied Regression, Second Edition. Thousand Oaks CA: Sage. URL: http://socserv.socsci.mcmaster.ca/jfox/Books/Companion
ggplot(faithful, aes(waiting, eruptions, color = eruptions > 3)) + geom_point() + stat_ellipse(type = "norm", linetype = 2) + stat_ellipse(type = "t")ggplot(faithful, aes(waiting, eruptions, color = eruptions > 3)) + geom_point() + stat_ellipse(type = "norm", linetype = 2) + stat_ellipse(type = "euclid", level = 3) + coord_fixed()