get_surface_distance: Compute geodesic distances on a surface mesh

In neuromapr: Spatial Null Models and Transforms for Brain Map Comparison

Compute geodesic distances on a surface mesh

Description

Builds a graph from a triangular mesh and computes shortest-path (Dijkstra) distances between vertices.

Usage

get_surface_distance(vertices, faces, source_vertices = NULL)

Arguments

vertices	Numeric matrix (n x 3) of vertex coordinates.
faces	Integer matrix (m x 3) of face indices (1-indexed).
source_vertices	Optional integer vector of source vertex indices. If NULL, computes the full n x n distance matrix.

Value

Numeric distance matrix. If source_vertices is provided, returns a ⁠length(source_vertices) x n⁠ matrix; otherwise an ⁠n x n⁠ matrix.

References

Markello RD et al. (2022) Nature Methods 19:1472-1480. doi:10.1038/s41592-022-01625-w

Examples

vertices <- matrix(
  c(0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1),
  nrow = 4, byrow = TRUE
)
faces <- matrix(c(1L, 2L, 3L, 2L, 3L, 4L), nrow = 2, byrow = TRUE)
get_surface_distance(vertices, faces)

neuromapr documentation built on Feb. 27, 2026, 5:08 p.m.