Simple and non-simple geometries
The values of linestrings, multipoints, and multilinestrings are considered either simple or non-simple.
A geometry is simple if it obeys all the topological rules imposed on its subtype and non-simple
if it does not.
- A linestring is simple if it does not pass through the same point twice except when the end points are the same point.
- A multipoint is simple if none of its elements occupy the same coordinate space.
- Points, polygons, multipolygons, and empty geometries are always simple.
Any linestring, multipoint, or multilinestring that does not adhere to the rules for a simple geometry is considered non-simple.