Acknowledgements

The paper is a personal viewpoint written while the author was a Visiting Scientist at the European Commission Joint Research Centre at Ispra, Italy. Notable contributions were made by Adam Gawne-Cain (cadcorp), Grant Ruwoldt (Bentley Systems, Inc.), Adrian Cuthbert (Laser-Scan Ltd.) and David Arctur (Laser-Scan, Inc.) in the Features Special Interest Group of the Open GIS Consortium Technical Committee's Core Task Force. Thanks are also due to the OGC staff who facilitated our work and showed that they understood what we were doing and why. No part of this paper should be construed as any intention by OGC to produce proposals for standards in this area.