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Points on Area Overlay: count points on multipart features

  • 14 September 2017
  • 3 replies
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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!

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Best answer by gio 14 September 2017, 14:51

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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.

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@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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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! :)

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