Validate an osm_graph

Checks that a graph meets the structural expectations the rest of the package relies on, and fails with one actionable bullet per problem found (all problems are collected first, so one run shows everything). Useful after assembling a graph by hand — a metro layer for ox_blend(), say — or after editing nodes/edges directly.

Usage

ox_validate(g, tolerance = 1e-06)

Arguments

g

An osm_graph.

tolerance

Maximum distance, in CRS units, between an edge geometry endpoint and its u/v node before it counts as a mismatch. Default 1e-6.

Value

g, invisibly, when the graph is valid; otherwise an error listing every problem found.

Details

The checks: nodes and edges are sf with POINT / LINESTRING geometries and no empty geometries, sharing one CRS; nodes$osmid exists, is numeric, complete and unique; edges$u/edges$v exist, are complete, and reference existing node osmids; edges$length exists, is numeric, complete and nonnegative; and each edge's geometry starts at its u node and ends at its v node (within tolerance, in CRS units) — the invariant that keeps routing results and drawn geometry in agreement.

Examples

g <- example_osm_graph()
ox_validate(g)
#> ✔ Valid <osm_graph>: 16 nodes, 48 edges.