Has anyone implemented this, or know if it would be difficult to implement this/have any pointers? public static SpatialRelationCriterion IsWithinDistance(string propertyName, object anotherGeometry, double distance) { // TODO: Implement throw new NotImplementedException(); } from NHibernate.Spatial.Criterion.SpatialRestrictions I can use "where NHSP.Distance(PROPERTY, :point)" in hql. But want to combine this query with my existing Criteria query. for the moment I'm creating a rough polygon, and using criteria.Add(SpatialRestrictions.Intersects("PROPERTY", myPolygon));