make_surf_graph: Build an igraph from a triangular surface mesh

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

Build an igraph from a triangular surface mesh

Description

Extracts unique edges from triangular faces, computes Euclidean edge weights, and returns an igraph graph object suitable for geodesic distance computation.

Usage

make_surf_graph(vertices, faces)

Arguments

vertices	Numeric matrix (n x 3) of vertex coordinates.
faces	Integer matrix (m x 3) of face indices (1-indexed).

Value

An igraph graph object with weighted edges.

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)
g <- make_surf_graph(vertices, faces)

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