Usage Notes - Advanced SQL Engine - Teradata Database

• The ST_IsValid method can be used to validate converted 2D geometries that were not validated by Make_2D.
• If the input geometry is already a 2D geometry value, this value is returned unchanged by this method.
• A well-formed 3D geometry value can become invalid during a 3D to 2D conversion. For example, if a 3D polygon lies in a plane parallel to the y axis, its line segments will self-intersect. Make_2D does not attempt to change the geometry type of the converted geometry from polygon to linestring to account for this, and an invalid 2D geometry can result.