Question

Can I use the NetworkTopologyCalculator to differentiate between different elevations (3D)?

  • 12 September 2016
  • 6 replies
  • 2 views
Y

Hi, I have a road network that I've been using the NetworkTopologyCalculator on to identify unconnected roads which I then discard to avoid drivers getting stick on an piece of road.

But, what I've just had pointed out to me is that my method isn't catching all unconnected roads. Some unconnected roads pass under/over the valid road network, touching nodes, which the

NetworkTopologyCalculator assumes are part of the valid road network. I have an elevation indicator for the start and end of each road segment, so I though by using the 3DInterpolator this would allow the

NetworkTopologyCalculator to identify that the roads were not touching at bridges/tunnels, but this does not seem to be the case.

Has anyone encountered such an issue, and if so are there any tools that might assist me here?

Thanks

Rich.

6 replies

itay
Rank
Badge +16

Hi,

The LineOnLineOverlayer can be used before the NetworkTopologyCalculator to intersect all lines and therefore making roads going under/over participate in the network analysis.

mark2atsafe
Rank
Userlevel 4
Badge +25

I don't think the NetworkTopologyCalculator handles Z values very well - but neither does any other transformer that you might use in this case.

I would try dropping all lines to points (Chopper) and testing for matching points. Use the Matcher with 3D geometry matching.

R
Badge

I don't think the NetworkTopologyCalculator handles Z values very well - but neither does any other transformer that you might use in this case.

I would try dropping all lines to points (Chopper) and testing for matching points. Use the Matcher with 3D geometry matching.

Hello @mark2atsafe

I ran into same issues. I need to analyse a 3D pipe network and FME is treating it as a 2D problem. Things seem to overlap in 2D, but in 3D they do not. :(

Are there any plans to give the 3D part of FME some upgrades?

mark2atsafe
Rank
Userlevel 4
Badge +25

Hello @mark2atsafe

I ran into same issues. I need to analyse a 3D pipe network and FME is treating it as a 2D problem. Things seem to overlap in 2D, but in 3D they do not. :(

Are there any plans to give the 3D part of FME some upgrades?

I honestly don't know what to suggest here. We are trying to improve all our 3D transformers, but I doubt that the TopologyBuilder is very high on this list. You may want to publish that as an idea on this site, and see if you can get other users to upvote it. I don't see an alternative method for creating a 3D topological network, except to isolate all of the line endpoints and do comparisons to see what matches. What I'll do is pass this on to our tech experts team, to see if anyone has experience of doing such a thing and if they are able to help further.

mark2atsafe
Rank
Userlevel 4
Badge +25

I honestly don't know what to suggest here. We are trying to improve all our 3D transformers, but I doubt that the TopologyBuilder is very high on this list. You may want to publish that as an idea on this site, and see if you can get other users to upvote it. I don't see an alternative method for creating a 3D topological network, except to isolate all of the line endpoints and do comparisons to see what matches. What I'll do is pass this on to our tech experts team, to see if anyone has experience of doing such a thing and if they are able to help further.

I checked with my colleague and there is currently nothing in FME designed to do this. But one colleague suggested there is a way we could implement this, given enough demand, so please do file this as an idea on this site if it is important and we will keep watch to gauge demand. Another colleague suggested the LineCombiner with "Consider Node Elevation" set to Yes might help, but I haven't been able to test that idea. Hopefully it will work if you try it out.

jdh
Rank
Badge +22

Hello @mark2atsafe

I ran into same issues. I need to analyse a 3D pipe network and FME is treating it as a 2D problem. Things seem to overlap in 2D, but in 3D they do not. :(

Are there any plans to give the 3D part of FME some upgrades?

The networkTopologyCalculator only sees connections at nodes. Is there a way to join you input data (ex lineCombiner - consider node elevation yes)) so there are no nodes at the false intersections.

 

 

If that is not possible, you could rig something up in python using graph theory and connected components.

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