I have several overlapping polygon layers and I want to dissolve all inner lines leaving just the outermost boundary to a couple of polygons then invert the layer revealing just the remaining area. What is the best workflow?
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Not sure I understand the question, but some transformers of interest could be
- Dissolver
- Clipper
- DonutBuilder
- DonutHoleExtractor
Maybe also look at the AreaOnAreaOverlayer and the _overlaps count attribute.
A small drawing of what you want to achieve would be helpful.
The Dissolver that @david_r suggests will combine overlapping or touching polygons into a single one. To invert the layer can use the Clipper but you'll need to have a polygon to clip from, which needs to be bigger than the polygon you're clipping with. Technically that can be solved by routing the dissolved polygons through a BoundingBoxAccumulator too and then put that into the Clipper as the Clipper feature with the original features as the Clippee, like this:
The question is: is this what you want? That bounding box would touch the extremes of the dissolved polygons, no extra margin around it.
I'd use a concave hull accumulator (rather then a BB) with a setting for alpha that just closes any boundary opening the dissolved polygons leave. (try halve distance of (smallest) opening).