I have a table with polygon geometry, in this case representing counties. I'm trying to figure out how to write a query that returns vertices sorted by the number of polygons that share that vertex. For example, think of the Four Corners ares of the United States where Arizona, Utah, Colorado, and New Mexico share a common corner.That corner would likely be at the top of the list, unless five states share a common vertex.
One thought I had, apply a 5' buffer to every vertex and return the polygons the buffer intersects. The logic seems like it would work but I suspect there is a better way.
I'm using PostgreSQL 9.5 Beta 1 with PostGIS 2.2.0 on Windows.