How to find points that lay on polygons in which another point layer exists by using FME 2021?

Question

I have 3 point feature classes (A,B and C) and 1 polygon feature class. I am trying to extract only features from feature class A that lay inside polygons which already containg features from feature class B or C. I tried "PointOnAreaOverlayer" and "SpatialRelator" Transformers but for some reason I dont get desired results. Any hint how this can be done in FME 2021 ?

Answer 1

I think you have the right transformers, but just need to use them in a specific way.

• So first add an attribute to the B and C point features. Let's call it BorC. Give it a value of 1
• Now use the PointOnAreaOverlayer to find which polygons B and C point features fall within. Make sure you copy the attributes from points to polygons. That way the polygons will now have the BorC attribute if they contain B or C points.
• Again use the PointOnAreaOverlayer to find A points that fall inside the polygons. Again transfer the attributes.

Now if an A point has the attribute BorC (test BorC = 1) then you'll know it falls inside a polygon that also includes a B or C point feature.

Answer 2

I've found Clipper to be straightforward for this. A nice feature of the transformer is that there are output ports for both features inside and outside the clip shape.