A commenter on my last ST_Donut post pointed out that we were essentially using not one but two buffers and and ST_Intersection to test where a point lay.  Bad Spatial SQL. Very bad Spatial SQL. Actually, at Paul Ramsey’s PostGIS for Power Users presentation at FOSS4G this year, I think he mentioned not doing that very thing, and I chuckled to myself, “Well, even I know better than that.” So much for false pride.

So here’s the revision, adapted as before from Sorokine:

Revised Oct 28th