OSGeometryTopology.xsd. Change of osgb namespace and removal of AbstractLineStringPropertyType. v2.4 2009/05/12 Ordnance Survey, (c) Crown Copyright. All Rights Reserved May 2009. See http://www.ordnancesurvey.co.uk for guidelines and related information This schema defines the geometry and topology extensions to GML 2.1.2. '+' Natural direction, '-' reverse direction