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Generates a geodesic mesh on the unit sphere by recursive subdivision of an icosahedron. Optionally refines around data locations using stereographic projection and local Delaunay triangulation.

Usage

tulpa_mesh_sphere(subdivisions = 3L, coords = NULL, radius = 1)

Arguments

subdivisions

Number of recursive icosahedral subdivisions. Each level quadruples the triangle count: 0 = 20 triangles, 1 = 80, 2 = 320, 3 = 1280, 4 = 5120, 5 = 20480. Default 3.

coords

Optional matrix of lon/lat coordinates (degrees) to insert into the mesh. Points are projected to the sphere and added as additional vertices via local re-triangulation.

radius

Sphere radius. Default 1 (unit sphere). For Earth, use 6371 (km).

Value

A tulpa_mesh object with components:

  • vertices: N x 3 matrix of (x, y, z) Cartesian coordinates on the sphere surface

  • triangles: M x 3 integer matrix of vertex indices (1-based)

  • edges: K x 2 integer matrix of edge vertex indices (1-based)

  • lonlat: N x 2 matrix of (longitude, latitude) in degrees

  • n_vertices, n_triangles, n_edges: counts

  • n_input_points: number of original input points

  • sphere: list with radius and subdivisions