Since 1995 a large number of industrial, academic and public members has formed the OpenGIS Consortium (OGC). The main purpose of OGC is to promote the interoperability ofGeoInformation systems (GIS). In order to achieve this goal, OGC defines a variety of OGCspecifications, e.g. for representation of geometry data, reference systems, and, most promi-nent, for OGC. OCG-conformant GIS are available for the representation of geographicaldata (“simple features”) and for web map server. In future, a GIS which is conform to theOGC service specifications, is able to interact with any other OGC-compliant system. Today,most OGC specifications are given as rather “abstract specifications”. For the representationof geometry data, the grid coverage, the transformation of coordinates and the Internet pre-sentation of maps there are concrete “implementation specifications”. Prices are just treatedas an unstructured attribute within an order.