Dr Lesley Arnold
Tel: 08 9273 7201 / Fax: 08 9273 7674
Assoc. Professor Graeme Wright
Tel: 08 9266 4800 / Fax: 08 9266 2682
Spatial scientists, and in particular national mapping agencies, are continually faced with the high cost of updating spatial information. Traditional techniques are extremely resource intensive. Organisations must revise both geographic and cartographic databases in order to maintain standards of geometric accuracy for GIS analysis and the arrangement of data for the production of maps at various scales. This process is time consuming and prone to human error.
at Curtin University of Technology in
DSU is implemented in a database-sharing and spatial views environment. Spatial views (map views) are virtual windows to an underlying geographic database, where updates to the database are reflected dynamically in all derived spatial views.
This paper examines the DSU process and demonstrates that by integrating a scale-independent data model, interactive cartographic display transformations and cartographic validation mechanisms, an integrated approach to spatial data maintenance and product management can be achieved.
DSU is enabled by encoding cartographic processes, such that map representations persist as graphic visualisations in spatial views. This persistence mechanism acts as a pseudo rule-base for update-propagation. Each time a spatial view is accessed, data and updates are automatically retrieved and the cartographic representation methods persistent in the view are automatically reapplied. In addition, a cartographic validation process has been developed to identify spatial conflicts that may occur at the map level after multiple iterations of updates to the database.
This approach supports centralised data management principles. Cartographic representations are stored latently in spatial views without impact to the underlying data source, which means the database remains constant and thus supports multi-user views. More significantly, the approach meets the needs of data users, who require flexibility to produce customised geographic data products from a primary data source and, at the same time, real-time updates for sustainable product management.