@Edent One issue with just using lat/lng/haversine is defining the area something applies to is often more complicated. eg "River Calder flooding" wants to go to specific places like Hebden Bridge, Todmorden, Mytholmroydeg "Good chance of northen lights in Scotland and North England tonight" is a massive area https://www.w3.org/TR/activitystreams-vocabulary/#dfn-place is a better link for saying what properties are allowed. Note "radius" which complicates search but still might not be enought to allow good definition! Activity Vocabulary