Oracle uses a series of specific spatial relationships to indicate the how different shapes interact with each other.
Two of the relationships it describes are somewhat odd:
OVERLAPBDYDISJOINT: The interior of one object intersects the boundary and interior of the other object, but the two boundaries do not intersect. This relationship occurs, for example, when a line originates outside a polygon and ends inside that polygon.
ON: The interior and boundary of one object is on the boundary of the other object. This relationship occurs, for example, when a line is on the boundary of a polygon.
Am I correct that these can never happen with two shapes that are the same inherent dimensionality? That is, a polygon can never have this relationship with another polygon, and a line can never have this relationship with another line. It can only happen if I have a point and a polygon, a line and a polygon, or a point and a line. Or have I misunderstood?