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Change detection on a WFS with restricted amount of features

  • May 3, 2021
  • 4 replies
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Hi all,

I'm trying to set up a change detection workspace, where I have a WFS that is my updated data and a ArcSDE, which is my original data.

 

I have added a Feature Reader, which grabs my WFS and the three relevant layers and used that as my Revised part in the Change Detector Transformer. The Original part comes from my ArcSDE Reader.

 

My problem is this: The WFS service usually has a maximum amount of features it will allow me to retrieve. I have different layers in the WFS which far exceed that maximum. Therefore my reader will only parse half of the features on to the Change Detector.

 

How do I get past this?

 

I tried adding a layer with polygons covering my area, and connecting it to my Feature Reader, setting the Spatial Filter to "Initiator intersects results". This should help the Feature reader, to only read the features within each polygon at a time, and then "ignore" the maximum amount restriction. But this doesn't seem to work, even though I've seen it work in another example..

Best answer by redgeographics

If it's a WFS 2.0 service you can use Resource Paging, in the WFS reader properties set the Start Index to 0 and Count to a value that's less than the limit, FME will then automatically split up the request into smaller chunks. Unless whoever set up that service disabled support for that...

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4 replies

redgeographics
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  • May 3, 2021

If it's a WFS 2.0 service you can use Resource Paging, in the WFS reader properties set the Start Index to 0 and Count to a value that's less than the limit, FME will then automatically split up the request into smaller chunks. Unless whoever set up that service disabled support for that...

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  • larsec
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  • 17 replies
  • May 3, 2021

Hi redgeographics,

 

Thanks for the tip. Is there a way to see if they have disabled it? I've tried setting it up as you recommended, but when I only run the WFS reader, it reads until the Count number I set, and stops.

redgeographics
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  • redgeographicsCelebrity
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  • May 3, 2021

Hi redgeographics,

 

Thanks for the tip. Is there a way to see if they have disabled it? I've tried setting it up as you recommended, but when I only run the WFS reader, it reads until the Count number I set, and stops.

That's probably a good sign that they have disabled that option (in which case that should be properly documented imho)

FME rocks! \m/
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  • larsec
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  • May 5, 2021

In my Feature reader solution (at the bottom of my original post) it seems to work with simple polygons. But if I use multipart polygons it doesn't work. Anyone know if this should work or if I'm trying something unsupported?

Thanks

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