geometryPrimitives.xsd See ISO/DIS 19136 Clause 11. Beside the "simple" geometric primitives specified in the previous Clause, this Clause specifies additional primitives to describe real world situations which require a more expressive geometry model. GML is an OGC Standard. Copyright (c) 2007,2010 Open Geospatial Consortium. To obtain additional rights of use, visit http://www.opengeospatial.org/legal/ . This property element either references a surface via the XLink-attributes or contains the surface element. A surface element is any element, which is substitutable for gml:AbstractSurface.