Between what kinds of polygon shapes would you have to differentiate?

Number of points can be an indicator, the angles of the polygon, the number of angles that are larger than 90 degrees, the lengths of the sides, is the polygon convex or concave, maybe the ratio between area and circumference, and much more.

Hi geomancer

We’re looking to basically classify non-square or rectangular polygons. 
These would have to be classified as pie shaped, L shaped, T shaped.

I think you’re right, an analysis of points, lines and angles could be very useful.

I found that initially excluding squares and rectangles (which we don’t care about) can be done by a bounding box transformer - then comparing the areas of both. They should be very similar

Perhaps some sort of AI tool or raster classification could also work?

The CircularityCalculator can find more circular features - https://docs.safe.com/fme/html/FME-Form-Documentation/FME-Transformers/Transformers/circularitycalculator.htm

For Circle, Square, you have bounding box and circularity approaches. L, or T shaped sounds like you’re interested in the number of concave parts of the shape.

You could Generalise it to remove noise/complexity, Thin, with a tolerance like half the distance across the polygon. HullReplacer, then clip it against itself to count the concave parts.

It’s difficult to know the limitations because it’s dependent on how you’ll use it.

A raster classification would be viable if one already exists. If it doesn’t then you have to weigh the time to make it, and how long it will be useful for.

Thanks everyone, I really appreciate the thoughtful responses!