This set of geoms and stats allows you to display voronoi tesselation and
delaunay triangulation, both as polygons and as line segments. Furthermore
it lets you augment your point data with related summary statistics. The
computations are based on the deldir::deldir()
package.
geom_voronoi_tile(mapping = NULL, data = NULL, stat = "voronoi_tile", position = "identity", na.rm = FALSE, bound = NULL, eps = 1e09, max.radius = NULL, normalize = FALSE, asp.ratio = 1, expand = 0, radius = 0, show.legend = NA, inherit.aes = TRUE, ...) geom_voronoi_segment(mapping = NULL, data = NULL, stat = "voronoi_segment", position = "identity", na.rm = FALSE, bound = NULL, eps = 1e09, normalize = FALSE, asp.ratio = 1, show.legend = NA, inherit.aes = TRUE, ...) geom_delaunay_tile(mapping = NULL, data = NULL, stat = "delaunay_tile", position = "identity", na.rm = FALSE, bound = NULL, eps = 1e09, normalize = FALSE, asp.ratio = 1, expand = 0, radius = 0, show.legend = NA, inherit.aes = TRUE, ...) geom_delaunay_segment(mapping = NULL, data = NULL, stat = "delaunay_segment", position = "identity", na.rm = FALSE, bound = NULL, eps = 1e09, normalize = FALSE, asp.ratio = 1, show.legend = NA, inherit.aes = TRUE, ...) geom_delaunay_segment2(mapping = NULL, data = NULL, stat = "delaunay_segment2", position = "identity", na.rm = FALSE, bound = NULL, eps = 1e09, normalize = FALSE, asp.ratio = 1, n = 100, show.legend = NA, inherit.aes = TRUE, ...) stat_delvor_summary(mapping = NULL, data = NULL, geom = "point", position = "identity", na.rm = FALSE, bound = NULL, eps = 1e09, normalize = FALSE, asp.ratio = asp.ratio, show.legend = NA, inherit.aes = TRUE, ...)
mapping  Set of aesthetic mappings created by 

data  The data to be displayed in this layer. There are three options: If A A 
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. 
na.rm  If 
bound  The bounding rectangle for the tesselation or a custom polygon
to clip the tesselation to. Defaults to 
eps  A value of epsilon used in testing whether a quantity is zero, mainly in the context of whether points are collinear. If anomalous errors arise, it is possible that these may averted by adjusting the value of eps upward or downward. 
max.radius  The maximum distance a tile can extend from the point of
origin. Will in effect clip each tile to a circle centered at the point with
the given radius. If 
normalize  Should coordinates be normalized prior to calculations. If

asp.ratio  If 
expand  A numeric or unit vector of length one, specifying the expansion amount. Negative values will result in contraction instead. If the value is given as a numeric it will be understood as a proportion of the plot area width. 
radius  As 
show.legend  logical. Should this layer be included in the legends?

inherit.aes  If 
...  Other arguments passed on to 
n  The number of points to create for each segment 
geom  The geometric object to use display the data 
geom_voronoi_tile and geom_delaunay_tile understand the following aesthetics (required aesthetics are in bold):
x
y
alpha
color
fill
linetype
size
geom_voronoi_segment, geom_delaunay_segment, and geom_delaunay_segment2 understand the following aesthetics (required aesthetics are in bold):
x
y
alpha
color
linetype
size
stat_delvor_summary computes the following variables:
If switch.centroid = TRUE
this will be the coordinates for
the voronoi tile centroid, otherwise it is the original point
If switch.centroid = FALSE
this will be the
coordinates for the voronoi tile centroid, otherwise it will be NULL
If switch.centroid = TRUE
this will be the
coordinates for the original point, otherwise it will be NULL
Number of triangles emanating from the point
The total area of triangles emanating from the point divided by 3
triarea
divided by the sum of the area of all
triangles
Number of sides on the voronoi tile associated with the point
Number of sides of the associated voronoi tile that is part of the bounding box
The area of the voronoi tile associated with the point
vorarea
divided by the sum of all voronoi tiles
# Voronoi # You usually wants all points to take part in the same tesselation so set # the group aesthetic to a constant (1L is just a convention) ggplot(iris, aes(Sepal.Length, Sepal.Width, group = 1L)) + geom_voronoi_tile(aes(fill = Species)) + geom_voronoi_segment() + geom_text(aes(label = stat(nsides), size = stat(vorarea)), stat = 'delvor_summary', switch.centroid = TRUE )#> Warning: stat_voronoi_tile: dropping duplicated points#> Warning: stat_voronoi_segment: dropping duplicated points#> Warning: stat_delvor_summary: dropping duplicated points# Difference of normalize = TRUE (segment layer is calculated without # normalisation) ggplot(iris, aes(Sepal.Length, Sepal.Width, group = 1L)) + geom_voronoi_tile(aes(fill = Species), normalize = TRUE) + geom_voronoi_segment()#> Warning: stat_voronoi_tile: dropping duplicated points#> Warning: stat_voronoi_segment: dropping duplicated points# Set a max radius ggplot(iris, aes(Sepal.Length, Sepal.Width, group = 1L)) + geom_voronoi_tile(aes(fill = Species), colour = 'black', max.radius = 0.25)#> Warning: stat_voronoi_tile: dropping duplicated points# Set custom bounding polygon triangle < cbind(c(3, 9, 6), c(1, 1, 6)) ggplot(iris, aes(Sepal.Length, Sepal.Width, group = 1L)) + geom_voronoi_tile(aes(fill = Species), colour = 'black', bound = triangle)#> Warning: stat_voronoi_tile: dropping duplicated points# Use geom_shape functionality to round corners etc ggplot(iris, aes(Sepal.Length, Sepal.Width, group = 1L)) + geom_voronoi_tile(aes(fill = Species), colour = 'black', expand = unit(.5, 'mm'), radius = unit(2, 'mm'))#> Warning: stat_voronoi_tile: dropping duplicated points# Delaunay triangles ggplot(iris, aes(Sepal.Length, Sepal.Width)) + geom_delaunay_tile(alpha = 0.3, colour = 'black')#> Warning: stat_delaunay_tile: dropping duplicated points# Use geom_delauney_segment2 to interpolate aestetics between end points ggplot(iris, aes(Sepal.Length, Sepal.Width)) + geom_delaunay_segment2(aes(colour = Species, group = 1), size = 2, lineend = 'round')#> Warning: stat_delaunay_segment2: dropping duplicated points