Find if 2 polygons have an intersection (Geoserver)

Question

I need to check if 2 polygons have at least one common point. What should be a proper CQL syntax for WFS request? And another variant if my 1st is not possible: get a list of polygons that have at least one common point or intersection with the source polygon?

Answer 1

The answers to these two questions are related. I'll answer the 2nd (easier) one first. You can test for at least a point in common using the Intersects test so a CQL filter like:

intersects(POLYGON((.....)), the_geom)

This will return all the features that intersect the geometry stored in the the_geom attribute.

To limit it to a specific feature you can extend the filter to request a specific feature such as:

in (1) and intersects(POLYGON((.....)), the_geom)

to return a feature if it's id is 1 and it intersects.