3.2.12. Tunnel schemaΒΆ


Fig. 3.50 Tunnel database schema

The tunnel model, described in Section 3.1.12 at the conceptual level, is realised by the tables shown in Fig. 3.50. The relational schema is identical to the building and bridge schema for the most parts except for the naming. Please, refer to the explanation of the building schema on the previous pages for a complete understanding. The main differences to the building schema are the following:

  • Tunnels cannot be modelled in LoD 0. Therefore, no corresponding columns appear in the TUNNEL table.
  • The CityGML feature HollowSpace can be seen analogue to the feature Room of a building or a bridge
  • CityGML features of tunnels, such as boundary surfaces, installations, openings, hollow spaces and furniture, are mapped to separate specific tables and are not stored in already existent ones (e.g. THEMATIC_SURFACE, OPENING). The reason for this is to provide a schema that is as close to the UML model as possible. There are slight differences between the building and the tunnel model that would lead to ambiguous references e.g. a boundary surface of the building namespace cannot reference to a tunnel feature.
  • OBJECTCLASS_ID of table TUNNEL_THEMATIC_SURFACE allows the values:
    • 89 (TunnelCeilingSurface),
    • 90 (InteriorTunnelWallSurface)
    • 91 (TunnelFloorSurface),
    • 92 (TunnelRoofSurface),
    • 93 (TunnelWallSurface),
    • 94 (TunnelGroundSurface),
    • 95 (TunnelClosureSurface),
    • 96 (OuterTunnelCeilingSurface),
    • 97 (OuterTunnelFloorSurface).
  • In the TUNNEL_INSTALLATION table external tunnel installations can be identified by the OBJECTCLASS_ID 86 and internal ones by 87.
  • The OBJECTCLASS_ID column in table BRIDGE_OPENING can be of integer value 100 (BridgeDoor) or 99 (BridgeWindow). They are associated to entries in the table TUNNEL_THEMATIC_SURFACE via the TUNNEL_OPEN_TO_THEM_SRF link table.
  • If a CityGML ADE is used that extends any of the named classes above, further values for OBJECTCLASS_ID may be added by the ADE manager. Their concrete numbers depend on the ADE registration (cf. Section 5.3.4).
  • In contrast to the building model tunnels and tunnel openings do not have addresses.