TopoGeo_AddLineString — Adds a linestring to an existing topology using a tolerance and possibly splitting existing edges/faces.
integer TopoGeo_AddLineString(varchar toponame, geometry aline, float8 tolerance
Adds a linestring to an existing topology and return a set of edge identifiers forming it up. The given line will snap to existing nodes or edges within given tolerance. Existing edges and faces may be split by the line.