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Create a Metric Graph Mesh

Source: R/graph.R
tulpa_mesh_graph.Rd

Builds a 1D FEM mesh along the edges of a spatial network (roads, rivers, coastlines). Each edge is discretized into segments with P1 linear elements. Junction nodes where edges meet are shared. Based on the Whittle-Matern SPDE formulation on metric graphs (Bolin, Simas & Wallin, 2024).

Usage

tulpa_mesh_graph(edges, max_edge = NULL, snap_tolerance = 1e-08)

# S3 method for class 'tulpa_mesh_graph'
print(x, ...)

Arguments

edges

A list of N x 2 coordinate matrices, each defining a polyline edge of the network. Or an sf object with LINESTRING geometries.

max_edge

Maximum segment length along edges. Edges longer than this are subdivided. Default NULL (use vertices as-is).

snap_tolerance

Distance below which endpoints are snapped to the same junction node. Default 1e-8.

x

A tulpa_mesh_graph object.

...

Additional arguments (ignored).

Value

A tulpa_mesh_graph object with components:

  • vertices: N x 2 matrix of node coordinates

  • segments: M x 2 integer matrix of segment connectivity (1-based)

  • n_vertices, n_segments: counts

  • C: consistent mass matrix (tridiagonal-block sparse)

  • G: stiffness matrix (tridiagonal-block sparse)

  • C0: lumped (diagonal) mass matrix

  • degree: integer vector of node degrees (junction = degree > 2)

The tulpa_mesh_graph object x, returned invisibly.