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- In BIMpedia
A building's operator gets an asset register and a model. A water company, an electricity network or a railway gets something different: its own GIS, which already holds thousands of kilometres of network, updated with what was built. The handover is a data load into the owner's system, and it either fits or it doesn't.
| Term | Meaning |
|---|---|
| Feature | One thing on the map: a pipe segment, a valve, a manhole, a cable |
| Attribute | A property of a feature: diameter, material, install date, owner ID |
| Schema (data model) | The owner's definition of feature types, attributes and code lists |
| Connectivity | Which features connect, so the network can be traced |
What to agree at the start
- The owner's schema: feature types, required attributes, code lists (materials, statuses), units.
- Identifiers: who issues asset IDs, and when.
- Connectivity rules: what must connect to what (pipes to fittings, cables to joints), and the tolerance for "connected".
- CRS and vertical datum: the owner's, not the project's, if they differ.
- Format: often GeoPackage, a file geodatabase or the owner's import template; from IFC 4.3 with georeferencing where the owner supports it.
- As-built evidence: how positions are surveyed, with accuracy and quality level, and when.
- Acceptance: the checks the owner runs, and a sample load before the full handover.
From model to GIS
The model holds the design and construction detail; the GIS needs a simpler, connected picture. A good handover maps each modelled element type to a GIS feature type, carries the agreed attributes, and adds connectivity and survey metadata the model may not hold. Test it with one section of the network months before completion, in the owner's real system.
At completion the contractor delivers a polished 3D model and a shapefile of pipe centre lines with diameters. The valves are separate points that don't touch the pipes, IDs are the contractor's own, and the coordinates are in the project grid. The owner's GIS team spends four months re-keying and reconnecting before the network can be used for burst isolation.
The owner's schema and ID rules are in the asset information requirements. The contractor records attributes as it builds, surveys each joint, and loads a 500 m section into the owner's test system in month six. Two attribute mistakes are found and fixed; the final load takes a day.
A water company will receive 6 km of new main with 14 valves, 3 hydrants and 2 meters. Write six lines for the asset information requirements so the data loads into its GIS.
Key takeaways
- The owner's GIS has its own data model: feature types, attributes, code lists and identifiers.
- Networks need connectivity (what connects to what), not just shapes, so operators can trace and isolate.
- As-built positions carry their survey method and accuracy, like any utility record.
- Agree format, CRS, identifiers and acceptance checks at the start, and test a sample early.