voronoi_diagram {ibawds}

Create a Voronoi Diagram for a Clustering

Description

Create a Voronoi diagram for a given clustering object.

Usage

voronoi_diagram(
  cluster,
  x,
  y,
  data = NULL,
  show_data = !is.null(data),
  colour_data = TRUE,
  legend = TRUE,
  point_size = 2,
  linewidth = 0.7
)

Arguments

cluster

an object containing the result of a clustering, e.g., created by kmeans(). It must contain the fields cluster and centers.

x, y

character giving the names of the variables to be plotted on the x- and y-axis.

data

The data that has been used to create the clustering. If this is provided, the extension of the plot is adapted to the data and the data points are plotted unless this is suppressed by specifying show_data = FALSE.

show_data

should the data points be plotted? This is TRUE by default if data is given.

colour_data

should the data points be coloured according to the assigned cluster?

legend

should a colour legend for the clusters be plotted?

point_size

numeric indicating the size of the data points and the cluster centres.

linewidth

numeric indicating the width of the lines that separate the areas for the clusters. Set to 0 to show no lines at all.

Details

The function uses the deldir package to create the polygons for the Voronoi diagram. The code has been inspired by ggvoronoi, which can handle more complex situations.

References

Garrett et al., ggvoronoi: Voronoi Diagrams and Heatmaps with ggplot2, Journal of Open Source Software 3(32) (2018) 1096, doi:10.21105/joss.01096

Examples

cluster <- kmeans(iris[, 1:4], centers = 3)
voronoi_diagram(cluster, "Sepal.Length", "Sepal.Width", iris)