[postgis-users] Splitting a Polygon with a Linestring

[James Beaudoin]

I think the steps below will work but I have one question. I am creating 
an application that allows a user to split a polygon by drawing a 
linestring across the polygon they wish to change. The crossing 
linestring has parts that are outside the polygon and I want to remove 
that before I geomunion. What's the easiest way to do that?

- extract the lines that make up the polygon
- add to this your crossing linestring
- geomunion the lines together.
- polygonize the union-ed set

Thanks,

Jim