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In a situation where you have geometry that sits physically within other geometry what is the right way to store and then represent this in QGIS?

Examples of this might include:

  • Cables running inside of ducts
  • Lanes running along roads
  • Fibre running inside of cables

And I guess n-level depth of this too, eg fibre inside of cable inside of duct.

I have found that you can create joins to help with the view side for labeling. I have also found you can do field lookups on the data entry form to aid with accurate/useful data entry.

My concern is that you would end up with lots and lots of lines all overlaid on top of each other all holding the same geometry data when really you're trying to represent non-geometry objects that sit "underneath" geometry objects.

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    – Ian Turton ♦
    Commented Aug 18, 2021 at 12:12
  • Understood, will expand
    – SimonJGreen
    Commented Aug 18, 2021 at 12:13
  • Storing in pretty clear: better to store them all. But what kind of representation in QGIS are you trying to achieve (what is the purpose of this representation)? A 2D Map (with offset) or 2.5D Map (with extrusion)?
    – Taras
    Commented Aug 18, 2021 at 12:30
  • It's to be able to document and interrogate for planning. In our particular use case I want to be able to document manholes and ducts, ducts and cables, cables and fibres, and how it all connects together.
    – SimonJGreen
    Commented Aug 18, 2021 at 12:48

1 Answer 1

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One polyline in the geographic map view then everything inside (eg ducts, cables & fibers) represented by using hierarchical data tree tables that have the ability to perform & represent the connectivity.

This person explains it well.

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