1. a School of Spatial Sciences , Curtin University of Technology , GPO Box U1987, Perth , WA , 6845
2. b School of Geomatic Engineering , The University of New South Wales , Sydney , NSW , 2052
3. c Centre for Spatial Information Science, School of Geography and Environmental Studies , The University of Tasmania , Hobart , Tas , 7001
4. d Research School of Earth Sciences , The Australian National University , Canberra , 0200 ACT
5. e School of Computing, Faculty of Information Sciences and Engineering , The University of Canberra , PO Box 1, Belconnen , 2616 ACT