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Tracing Multiple Networks from Sources to Valves Without Python

  • July 9, 2025
  • 2 replies
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femo
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Hi everyone,

I'm working with a topologically accurate line network in FME 2023.1.1.1. I have:

  • Two source points located at the start points of some lines (also refer to pipe-network_plus_point-features.png)→ the blue rhombus
  • Valves represented as point features, located somewhere along the lines (not necessarily at endpoints)→ the magenta colored points

My goal is to identify all topologically connected lines starting from each of the sources and continuing until the valves are reached. Each group of connected features should be treated as a separate subnetwork. In this case, I expect to identify two distinct subnetworks, one for each source. Also refer to desired_result.png and the detail 1 and 2.

Has anyone tackled something similar? I’m looking for a solution that ideally avoids using Python and relies on standard FME transformers (e.g., using loops or topology-based logic).

Any suggestions or best practices would be greatly appreciated!

Thanks in advance

Best answer by ebygomm

When i’ve done something similar for a road network, i stored all the original geom as an attribute, buffered what would have been equivalent to the valves in your example by a very small amount and used them to clip the network. Then used the network topology calculator to identify lines belonging to the same network, then reinstated the original line geometry. 

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ebygomm
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  • July 9, 2025

When i’ve done something similar for a road network, i stored all the original geom as an attribute, buffered what would have been equivalent to the valves in your example by a very small amount and used them to clip the network. Then used the network topology calculator to identify lines belonging to the same network, then reinstated the original line geometry. 


femo
Contributor
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  • July 10, 2025

Hi ​@ebygomm,

thanks a lot for your advices that really have led me to a solution!