Q&A

This page collects recurring questions whose answers are not obvious from a single model page. For the underlying rules, see Model At A Glance and OpticalPath.

NoteHow should coordinates work?

All coordinate-bearing objects are interpreted using the inventory-level CoordinateReferenceSystem, which defines coordinate_labels:

coordinate_reference_system:
  authority: EPSG
  code: 4979
  name: WGS 84 3D
  coordinate_labels: [longitude, latitude, elevation]
  units: [degree, degree, meter]

Point-like objects such as Station and Channel accept either a generic coordinates tuple ordered by those labels or dynamic fields named by them:

stations:
  - code: VA01
    coordinates: [2.103905, 48.807461, 115.0]
  - code: VA02
    longitude: 2.104
    latitude: 48.808
    elevation: 116.0

Fiber geometry uses the same CRS but stores coordinate sequences along optical distance.

NoteHow should unknown sections be represented?

Leave them uncovered — partial coverage is undefined, not invalid. To distinguish known-unknown from merely unrecorded, add an annotation:

annotations:
  - start_distance: 0.0
    end_distance: 50.0
    group: unknown_lead_in

Later geometry or coupling updates can fill the interval.

NoteHow should fiber coils or clumps be represented?

As ordinary optical path length with compact geometry: a FiberSegment in the ordered components, and a Geometry segment whose coordinates repeat while distance advances. Add coupling (coupling_type: coiled) or an annotation so consumers know the compact geometry is intentional, not missing survey detail:

geometry:
  - name: Vault 2 coil location
    distance: [1200.0, 1300.0]
    coordinates:
      - [500.0, 120.0, 0.0]
      - [500.0, 120.0, 0.0]

annotations:
  - start_distance: 1200.0
    end_distance: 1300.0
    group: slack_coil
    description: Stored coil, not intended as sensing fiber.