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LineOnLineOverlayer for Dynamic Segmentation

jonathanchiang0
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Dear expert of Dynamic Segmentation:

I was using LineOnLineOverlayer for Dynamic Segmentation purpose, but it was giving me wrong attribute information. I've got 2 segments or event layers here, all with geometry:

The ideal result I was looking for is:

But the result generated by LineOnLineOverlayer is:

Looking at the result in FME Inspector, the geometries of the 3 segments are at the right place, just the attributes are all messed up, specifically 1st and 2nd row. I didn't find too much information about using FME for linear referencing stuff, so I have to turn to this forum.

I hope gio and takashi or anybody with previous experience could provide some insights on this. Much appreciated. Thanks!

@gio

@takashi aand

 

Best answer by itay

As mentioned above the transformer does not overwrite attributes by default, see the image below for the attribute accumulation settings and List generation (list elements cannot be viewed in the table view of the Data Inspector, but only in the Feature Information Window)

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11 replies

erik_jan
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  • erik_janContributor
  • Contributor
  • May 15, 2017

The reason is that the LineonLineOverlayer does not overwrite existing attributes.

I would prefix attributes from both sources and the combine the two (maximum from and minimum to) to get the right values.

If the attribute exists on both sources one of the two (kind of random) will be used.

takashi
Influencer
  • takashiInfluencer
  • May 16, 2017

Hi @jonathanchiang0, I think this workflow works for you if the values of "from" and "to" are consistent with (i.e. equal to or in proportion to) the actual measure values of the line vertices.

  1. MeasureSetter x 2: Set the "from" and "to" values to measures of start/end vertex for each line.
  2. MeasureInterpolator (from FME Hub): Generate measures of other vertices.
  3. LineOnLineOverlayer: Perform segmentation.
  4. MeasureExtractor x 2: Extract the measure values of start/end vertex as new "from" and "to" for each segment.

itay
Supporter
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  • itaySupporter
  • Supporter
  • Best Answer
  • May 16, 2017

As mentioned above the transformer does not overwrite attributes by default, see the image below for the attribute accumulation settings and List generation (list elements cannot be viewed in the table view of the Data Inspector, but only in the Feature Information Window)

jonathanchiang0
Contributor
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erik_jan wrote:

The reason is that the LineonLineOverlayer does not overwrite existing attributes.

I would prefix attributes from both sources and the combine the two (maximum from and minimum to) to get the right values.

If the attribute exists on both sources one of the two (kind of random) will be used.

Thank you for the reply. LineonLineOverlayer worked, after a little tweaking with parameters and other transformers. But what about scalability? I was testing with 3 event layers containing half a million records. The process ran for 18 hours before I stopped it this morning. And I have 36 layers ...

 

 

jonathanchiang0
Contributor
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takashi wrote:

Hi @jonathanchiang0, I think this workflow works for you if the values of "from" and "to" are consistent with (i.e. equal to or in proportion to) the actual measure values of the line vertices.

  1. MeasureSetter x 2: Set the "from" and "to" values to measures of start/end vertex for each line.
  2. MeasureInterpolator (from FME Hub): Generate measures of other vertices.
  3. LineOnLineOverlayer: Perform segmentation.
  4. MeasureExtractor x 2: Extract the measure values of start/end vertex as new "from" and "to" for each segment.

Thank you for the reply. LineonLineOverlayer worked, after a little tweaking with parameters and other transformers. But what about scalability? I was testing with 3 event layers containing half a million records. The process ran for 18 hours before I stopped it this morning. And I have 36 layers ...

 

 

jonathanchiang0
Contributor
Forum|alt.badge.img
itay wrote:

As mentioned above the transformer does not overwrite attributes by default, see the image below for the attribute accumulation settings and List generation (list elements cannot be viewed in the table view of the Data Inspector, but only in the Feature Information Window)

Thank you for the reply. LineonLineOverlayer worked, after a little tweaking with parameters and other transformers. But what about scalability? I was testing with 3 event layers containing half a million records. The process ran for 18 hours before I stopped it this morning. And I have 36 layers ...

 

takashi
Influencer
  • takashiInfluencer
  • May 17, 2017
jonathanchiang0 wrote:
Thank you for the reply. LineonLineOverlayer worked, after a little tweaking with parameters and other transformers. But what about scalability? I was testing with 3 event layers containing half a million records. The process ran for 18 hours before I stopped it this morning. And I have 36 layers ...

 

 

If "id" and/or "streetname" can be used to group the segments for the same road, try setting the attribute(s) to the Group By parameter of the LineOnLineOverlayer.

 

itay
Supporter
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  • itaySupporter
  • Supporter
  • May 17, 2017
jonathanchiang0 wrote:
Thank you for the reply. LineonLineOverlayer worked, after a little tweaking with parameters and other transformers. But what about scalability? I was testing with 3 event layers containing half a million records. The process ran for 18 hours before I stopped it this morning. And I have 36 layers ...

 

I would segment the data by tiling it and use the parallel processing capabilities of the transformer, dont forget to set the group by setting (otherwise the parallel processing wont work)

 

 

erik_jan
Contributor
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  • erik_janContributor
  • Contributor
  • May 17, 2017
jonathanchiang0 wrote:
Thank you for the reply. LineonLineOverlayer worked, after a little tweaking with parameters and other transformers. But what about scalability? I was testing with 3 event layers containing half a million records. The process ran for 18 hours before I stopped it this morning. And I have 36 layers ...

 

 

Could you use the Group by on the LineomLineOverlayer and for example set it to the streetname?

 

That way you could use the parallel processing and get a faster result.

 

You will find transformer information here

 

 

notmyname
Participant
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  • notmynameParticipant
  • Participant
  • November 2, 2017
itay wrote:

As mentioned above the transformer does not overwrite attributes by default, see the image below for the attribute accumulation settings and List generation (list elements cannot be viewed in the table view of the Data Inspector, but only in the Feature Information Window)

@jonathanchiang0 Did you ever find a scalable method?

 

M
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itay wrote:

As mentioned above the transformer does not overwrite attributes by default, see the image below for the attribute accumulation settings and List generation (list elements cannot be viewed in the table view of the Data Inspector, but only in the Feature Information Window)

if you have different width (I suppose that the width of street), did you recalculate the width between 33.33 and 66.67? Or how we can recalculte the width?

 

 

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