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Points on Area Overlay: count points on multipart features

  • September 14, 2017
  • 3 replies
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pinkopo
Contributor
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Hi guys,

I am trying to use point overlay to get a point count over polygons, but everytime the Point Area Overlay transformer seems explode the multi-parts polygons. Is there anyway i can avoid this?

Thanks!

Best answer by gio

@sangli

You can also use a spatialrelator for this. The geometry will not be exploded.

If you have points as supplier (test = contains), you can us a listelementcounter to count the elements in the list.

If you have points as requestor (test = Within), you can use a Statistics calculator grouped by the area id to count the points within.

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3 replies

takashi
Celebrity
  • 7843 replies
  • September 14, 2017

Hi @sangli, currently there is no way to prevent exploding (de-aggregating) input multi-part areas, unfortunately. A possible workaround is: use the Aggregator to aggregate the output areas.

  • Group By: <set unique ID attribute of original areas>
  • Attributes to Sum: <set the Overlap Count Attribute specified in the PoinOnAreaOverlayer>

If the original area features don't have unique ID attribute, you can use a Counter to add sequential number to the features as temporary ID before inputting them to the PointOnAreaOverlayer.


gio
Contributor
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  • Contributor
  • 2252 replies
  • Best Answer
  • September 14, 2017

@sangli

You can also use a spatialrelator for this. The geometry will not be exploded.

If you have points as supplier (test = contains), you can us a listelementcounter to count the elements in the list.

If you have points as requestor (test = Within), you can use a Statistics calculator grouped by the area id to count the points within.


pinkopo
Contributor
Forum|alt.badge.img+5
  • Author
  • Contributor
  • 22 replies
  • September 15, 2017

Hi @sangli, currently there is no way to prevent exploding (de-aggregating) input multi-part areas, unfortunately. A possible workaround is: use the Aggregator to aggregate the output areas.

  • Group By: <set unique ID attribute of original areas>
  • Attributes to Sum: <set the Overlap Count Attribute specified in the PoinOnAreaOverlayer>

If the original area features don't have unique ID attribute, you can use a Counter to add sequential number to the features as temporary ID before inputting them to the PointOnAreaOverlayer.

Thank you Takashi that's a great idea! :)