Given a LineString and a Polygon, detect which Polygon nodes are above or below the LineString

Question

I have a Shapely Polygon and a LineString. I want to be able to determine which Polygon points are above the LineString and which are below. Alternatively, it would also be alright if I were to splice a Polygon using a LineString and generate two new Polygons.

Are there any built-in Shapely methods that would allow me to do this?

Answer 1

In case anyone else comes searching for this, you can use this to split the polygon into to sub-polygons and work from there:

merged = linemerge([poly.boundary, line])
borders = unary_union(merged)
polygons = polygonize(borders)

Check out this other post in support of this approach.