STDisjoint

STDisjoint is a spatial predicate function commonly found in Geographic Information Systems (GIS) and spatial database extensions, such as PostGIS and SQL Server. Its purpose is to determine if two geometric objects do not intersect in space, meaning they have no common points.

The function takes two geometries as input and returns a boolean value. If the geometries are entirely separate and do not touch at any point, including boundaries, STDisjoint returns TRUE. If the geometries share any common point, whether on their interiors or boundaries, it returns FALSE.

For example, if you have two polygons representing parcels of land, STDisjoint would return TRUE if one parcel is entirely to the north of the other, with no overlap. Conversely, if the parcels share a boundary or overlap, STDisjoint would return FALSE. Similarly, for points and lines, STDisjoint would return TRUE if a point does not lie on a line and is not coincident with it, or if two lines do not cross or share any points.

STDisjoint is an efficient way to perform spatial checks and is fundamental for many GIS operations, including spatial indexing, data validation, and complex spatial analysis. It is the logical inverse of the STIntersects predicate.