GIS for utilities and rail
How do BIM and GIS work together on a utility or rail project?
Understand6
What it is, in plain language
- Pedia · BIM + GISStationing and chainageHow positions are given along a linear project: the distance along a named alignment (chainage or stationing) and the offset from it.
- Pedia · BIM + GISIfcAlignmentThe IFC 4.3 entity that describes a road, rail or other alignment with its horizontal, vertical and cant parts, so elements can be placed along it.
- Pedia · BIM + GISUtility quality levelsThe grading of existing utility information by how it was obtained, from records only (D) to exposed and measured (A), used by PAS 128 in the UK and ASCE 38 in the US.
- Pedia · BIM + GISCombined scale factorThe factor that converts distances between a map grid and the ground: grid scale factor times elevation factor. Small per metre, large over a long corridor.
- Pedia · BIM + GISUtility network recordsThe owner's records of its pipes, cables and fittings, usually in GIS: features with attributes and connectivity, used to operate, maintain and isolate the network.
- Pedia · BIM + GISTrack geometryThe shape of a railway track in plan and profile, plus the cant between the rails, within tight tolerances: what designers set and maintainers keep.
Learn6
Short lessons with a quick check
- Lesson · 3 min · quizGIS on linear projectsRoads, railways, pipelines and cables run for kilometres across land owned by many people, under rivers and roads, past protected sites and existing networks. That is GIS territory. BIM covers the structures along the way; GIS holds the corridor they sit in.
- Lesson · 4 min · quizAlignments and chainageOn a linear project, everything is located by its distance along the alignment and its offset from it. That distance is called chainage (or stationing in the US, mileage on older railways). Learn to read it, and to check a vertical curve from a real drawing.
- Lesson · 3 min · quizUtility records and quality levelsMost existing pipes and cables are known only from the owners' records, which may be decades old and metres out. Utility survey standards grade every line by how it was found, from a desktop record to a line exposed and measured. The grade decides how close you may design and dig.
- Lesson · 3 min · quizCoordinates over long corridorsA map grid is a flat picture of a curved Earth, so distances on the grid differ slightly from distances on the ground. Over a building nobody notices; over a 20 km railway it adds up to decimetres or metres. The scale factor turns one into the other.
- Lesson · 3 min · quizRail for BIM peopleA railway is a system of systems: track, structures, overhead power, signalling, telecoms and drainage, all working within millimetres along hundreds of kilometres, and all built while trains keep running nearby. Here is what a BIM coordinator needs to know to work on one.
- Lesson · 3 min · quizHanding over to GISWhen a utility or rail project finishes, the owner doesn't want a model: it wants its network updated in its own GIS, with the right attributes, connected correctly, in its coordinate system, so that operators can find, maintain and isolate every asset.
Do2
Tools that export your work
Mayainformation manager
The one I see most often on real projects: treating utility records as surveyed positions. Tick off the checklist as you put each thing in place.
Common mistakes
What goes wrong most often on real projects.
- Treating utility records as surveyed positions.
- Using grid distances on a long corridor without the scale factor.
- Handing over a utility network without the owner's attribute schema.
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Tick what is done — it counts towards the checkpoint on your learning path.
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