Density Estimate (ggtern version)

Description

Perform a 2D kernel density estimatation using kde2d and display the results with contours. This can be useful for dealing with overplotting. Additional weight aesthetic (see aesthetic section below) permits better weighting if desired

Aesthetics

geom_density_tern understands the following aesthetics (required aesthetics are in bold):

  • x
  • y
  • alpha
  • colour
  • linetype
  • size
  • weight

Usage

geom_density_tern(mapping = NULL, data = NULL, stat = "DensityTern", position = "identity", ..., lineend = "butt", linejoin = "round", linemitre = 1, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)


stat_density_tern(mapping = NULL, data = NULL, geom = "density_tern", position = "identity", ..., contour = TRUE, n = 100, h = NULL, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, weight = 1, base = "ilr", expand = c(0.5, 0.5))

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.
stat
The statistical transformation to use on the data for this layer, as a string.
position
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.
lineend
Line end style (round, butt, square)
linejoin
Line join style (round, mitre, bevel)
linemitre
Line mitre limit (number greater than 1)
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.
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
Use to override the default connection between geom_density_2d and stat_density_2d.
contour
If TRUE, contour the results of the 2d density estimation
n
number of grid points in each direction
h
Bandwidth (vector of length two) as a multiple of the best estimate, estimated using bandwidth.nrd.
weight
weighting for weighted kde2d esimate, default's to 1, which is non-weighted and equivalent to the usual kde2d calculation
base
the base transformation of the data, options include 'identity' (ie direct on the cartesian space), or 'ilr' which means to use the isometric log ratio transformation.
expand
Calculate on a mesh which extends beyond the grid of the plot region by this amount If NULL, estimated using bandwidth.nrd.

Examples

#Plot Density Estimate, on isometric log ratio transformation of original data
data('Feldspar')
ggtern(Feldspar,aes(Ab,An,Or)) + 
 geom_density_tern(aes(color=..level..),bins=5) +
 geom_point()






#Plot Density Estimate w/ Polygon Geometry
data('Feldspar')
ggtern(data=Feldspar,aes(Ab,An,Or)) + 
    stat_density_tern(
        geom='polygon',
        aes(fill=..level..),
        bins=5,
        color='grey') +
    geom_point()