Skip to contents

Generate random ellipses constrained by a point cloud and a reference ellipse

Source: R/virtual_comunities.R
random_ellipses.Rd

Creates n random ellipses with centroids sampled from an irregular point cloud. Covariance matrices are built using random rotations and scaled eigenvalues restricted by user-defined limits.

Usage

random_ellipses(
  object,
  background,
  n = 10,
  smallest_proportion = 0.1,
  largest_proportion = 1,
  thin_background = FALSE,
  resolution = 50,
  seed = 1
)

Arguments

object

A nicheR_ellipsoid object used as a reference ellipse (the biggest to be generated), and containing at least covariance_matrix and cl.

background

Matrix or Dataframe. The 2D point cloud (coordinates) used to select random centroids.

n

Integer. Number of ellipses to generate.

smallest_proportion

Numeric. Minimum scaling factor for the variance. Must be between 0 and 1. Default = 0.1. This controls how much smaller the new ellipses can be compared to the reference.

largest_proportion

Numeric. Maximum scaling factor for the variance relative to the reference. Default = 1.0. This controls how much larger the new ellipses can be compared to the reference. Values larger than 1 will result in ellipses that exceed the reference size.

thin_background

Logical. If TRUE, centroids are sampled more uniformly across the background using a grid-based thinning approach. Default = FALSE.

resolution

Integer. Number of cells per side in the grid to deal with point density variation across background. Default = 50.

seed

Integer. Random seed for reproducibility. Default = 1. Set to NULL for no seeding.

Value

An object of class nicheR_community containing the generated ellipses, the reference object, and generation metadata.