Check a build

Validation during the build

Switch validation on in your config file. The build then checks its own result and fails if something is wrong:

validation:
  enabled: true

It's off by default (and a build from the command line alone can't switch it on), but the config template turns it on. On Monaco it prints, per mode:

validate[driving] single_component: OK — 1 component(s), largest 2,765/2,765 (100.0%)
validate[driving] no_stranded_named: OK — 0 named edge(s) outside the largest component
validate[driving] unique_node_id: OK — 0 duplicate node_id(s) in nodes
validate[driving] way_length_conserved: OK — 0 deleted parallel arc(s) (way stretch missing while a kept edge bridges its endpoints)
validate[driving] layer_without_structure: WARN — 11 edge(s) with layer≠0 but no bridge/tunnel tag (OSM tagging; drawn grade-separated, no 3D deck)

Check	Fails the build when
single_component	the network isn't one connected piece
no_stranded_named	a named road sits outside the main network
unique_node_id	two nodes share an id
way_length_conserved	part of an OSM way went missing when it was split into edges
layer_without_structure	never: a warning about OSM tagging (a road on another level with no bridge or tunnel tag)

The first two only run when the build has a boundary: a whole region can legitimately have separate pieces (islands, for example). Each check can be switched off; see Configuration. Set fail_on_error: false to be warned instead of stopped.

A report of the build

With report: {enabled: true} in the config, the build also writes a summary to reports/ as Markdown and HTML: counts per mode, what the road filter kept and dropped, the network pieces, and the validation results.

Check the geometry

In a clone of the repo, scripts/validate_geometry.py checks that every edge's geometry starts and ends at its nodes, and that there are no loops or zero-length edges (driving and walking networks):

python scripts/validate_geometry.py --db monaco.duckdb

Validating Geometry for Mode: driving
  ✓ No self-loops found.
  ✓ All edge endpoints match their topological nodes.
  ✓ No degenerate (zero-length) geometries.
...
ALL GEOMETRY CHECKS PASSED!

To look at one street in detail, see Look up one OSM way.