Merge attributes from overlaying features - Best practice

The LineOnLineOverlayer has the standard Attribute Accumulation settings, one of them being "Merge Attributes". If you are certain there's not going to be a conflict that is probably the easiest thing to do.

Other than that it offers the option to create a list, you could use that to deal with conflicts, but exactly how depends on what you want to do with those conflicts.

You can do this using the advanced settings in the AttributeCreator as shown below:

Hope this helps

@redgeographics, I have been trying various spatial transformers in combination with list. But so far I have not been able to achieve consistent results. I end up with far to many "what's and if's" that need to be compensated for.

@erik_jan Interesting!

This is a new method that I have not explored before. I will definitely try this!

A follow up question: From the documentation I get the impression that one needs to set a number for the features that are to be taken into account?. Is there a way to set this to 'all', for those instaces where the number is unknown? Or can one use _countedoverlays to achieve this?

Can you share a specific example (data + your workspace)?

@aron . Perhaps overthinking this. Below works for me.

So long as the Value Attributes for B, C, D and E are all named differently from each other, then there is no Attribute Name conflicts when SpatialRelator merges first A, then B, then C, then D, then E. If there are no features that overlay from B, C, D or E, then that will show as "Missing" in the output of for any of A's Features exiting the Transformer.

Thing is that they share the same names.

There could be 5 overlaping lines or none. Feature 1 could have attributes A and C and feature two could have B and D. Or feature 1 could have A, B and C - and feature 2 and 3 could have none of theese attributes. I need to build a workplace that can adapt to varying inputs

There is more info from earlier in my build process. https://knowledge.safe.com/questions/106417/merge-attributes-from-mulitple-features-onto-new-o.html?childToView=106439#answer-106439

If I understood your requirement correctly, this workflow might help you.

1. TopologyBuilder: Build networks from the original lines.
2. NetworkTopologyCalculator: Add network ID which is unique for each connected network to the network edges.
3. SpatialFilter: Merge the network ID to the original lines according to the spatial relationships.
4. Aggregator (Group By: network ID, Accumulation Mode: Merge Incoming Attributes): Aggregate the lines grouping by the network ID and merge the their attributes.