create_voronoi_plot: Create Voronoi Tesselation Visualization Plot

In VoronoiBiomedPlot: Tesselation Visualization Plots for 2D Data

Create Voronoi Tesselation Visualization Plot

Description

Creates a Voronoi tessellation visualization for 2D projected data, showing class separation through proximity-based regions.

Usage

create_voronoi_plot(
  data,
  class_column = NULL,
  alternative_class_column = NULL,
  coordinate_columns = NULL,
  case_labels = NULL,
  coord_names = c("Dim1", "Dim2"),
  title = NULL,
  show_labels = FALSE,
  voronoi_alpha = 0.3,
  point_size = 2,
  legend_position = "bottom",
  color_palette = NULL,
  add_grid_lines = FALSE,
  color_points = "primary",
  fill_voronoi = "primary",
  point_shape = "none",
  label_fontface = "plain",
  label_size = 3.88,
  show_island_count = FALSE,
  label_islands_only = FALSE
)

Arguments

data	A data frame containing projected data. Must have at least 2 numeric columns. If more than 2 columns are provided, the first 2 are used as coordinates.
class_column	Character string specifying the column name containing class labels, or a vector of class labels. If NULL, all observations are treated as a single class. Default: NULL.
alternative_class_column	Character string specifying the column name containing alternative class labels, or a vector of alternative class labels. If NULL, uses class_column. Default: NULL.
coordinate_columns	Character vector of length 2 specifying the column names to use as coordinates. If NULL, uses the first two numeric columns. Default: NULL.
case_labels	Character vector of case labels for individual observations. If NULL, row numbers are used. Default: NULL.
coord_names	Character vector of length 2 specifying names for the coordinate axes. Default: c("Dim1", "Dim2").
title	Character string for plot title. If NULL, no title is added. Default: NULL.
show_labels	Logical indicating whether to show case labels on plots. Default: FALSE.
voronoi_alpha	Numeric value (0-1) for Voronoi polygon transparency. Default: 0.3.
point_size	Numeric value for point size. Default: 2.
legend_position	Character string or numeric vector specifying legend position. Default: "bottom".
color_palette	Function or character vector for color palette. If NULL, uses ggplot2 default colors. Default: NULL.
add_grid_lines	Logical indicating whether to add dashed grid lines at origin. Default: FALSE.
color_points	Character string specifying which classification to use for point colors. Either "primary" (uses class_column) or "alternative" (uses alternative_class_column). Default: "primary".
fill_voronoi	Character string specifying which classification to use for Voronoi fill. Either "primary" (uses class_column) or "alternative" (uses alternative_class_column). Default: "primary".
point_shape	Character string specifying which classification to use for point shapes. Either "primary" (uses class_column), "alternative" (uses alternative_class_column), or "none" (no shape differentiation). Default: "none".
label_fontface	Character string specifying the font face for text labels. Options include "plain", "bold", "italic", "bold.italic". Default: "plain".
label_size	Numeric value specifying the size of text labels. Default: 3.88.
show_island_count	Logical indicating whether to display the Voronoi island count as a plot subtitle. A Voronoi island is a data point whose cell is entirely surrounded by cells belonging to a different class. The count and rate (proportion of all cells that are islands) are shown as a subtitle when TRUE. The island count is always computed using the primary class labels (class_column), regardless of the fill_voronoi setting. Default: FALSE.
label_islands_only	Logical indicating whether to show case labels on plots only for Voronoi islands. Default: FALSE.

Details

The function creates a Voronoi tessellation visualization for 2D data, particularly useful for displaying results from dimensionality reduction techniques. Voronoi tessellation divides the plot space into regions based on proximity to data points, providing an intuitive visualization of class boundaries and decision regions.

The Voronoi island count is a visualization-intrinsic metric with no equivalent in confidence ellipse approaches. Neighbor relationships are determined from the Delaunay triangulation (the dirsgs component of the deldir output), which is the geometric dual of the Voronoi tessellation: two cells share an edge if and only if their corresponding points are connected by a Delaunay edge. A cell is classified as an island if all its Voronoi neighbors belong to a different class. Island detection requires no additional computation beyond the tessellation itself.

Value

A ggplot object showing the Voronoi tessellation plot. If show_island_count = TRUE, the plot subtitle displays the number of Voronoi islands and the island rate (proportion of all cells that are islands).

Examples

# Basic usage with iris dataset
data <- iris[, c("Sepal.Length", "Petal.Length", "Species")]
plot <- create_voronoi_plot(
  data = data,
  class_column = "Species",
  legend_position = "bottom",
  add_grid_lines = FALSE
)

# With Voronoi island count displayed as subtitle
plot <- create_voronoi_plot(
  data = data,
  class_column = "Species",
  legend_position = "bottom",
  add_grid_lines = FALSE,
  show_island_count = TRUE
)

VoronoiBiomedPlot documentation built on April 25, 2026, 9:06 a.m.