I am new to FME/GIS and using FME 2015. I have a current layer of polygons and a new layer of polygons. I am comparing the layers to determine changes. I am using AreaOnAreaOverlayer to get a new set of polygons with the merged attributes. This worked well until I received a dataset with a slight shift/offset in the polygons between the layers that is not visible when looking at them layered on top of each other. The layers look like the polygons overlap exactly and would result in one new polygon for each overlap. But instead, the AreaOnAreaOverlayer is generating a lot of new small polygons for the border around the polygons. This runs for a long time. Is there any suggestions on how best to handle this type of situation to prevent all of these new polygons from being generated?
+17- Contributor
You could create a center point for one of the two sets (CenterPointCreator) and the use the PointOnAreaOverlayer to check what point is in what polygon.
If the offsets are tiny, consider using FME 2018 which has improved a lot in this regard.
Another solution would be to use the Snapper (or the AnchoredSnapper) in segment snapping mode before the AreaOnAreaOverlayer. The snapping tolerance should be around the offset distance that you're observing, preferably without introducing false positives.
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