Dr Lesley Arnold
Tel: 08 9273 7201 / Fax: 08 9273 7674
Email: lesley.arnold@landgate.wa.gov.au
Assoc. Professor Graeme Wright
GPO
Tel: 08 9266 4800 / Fax: 08 9266 2682
Email: G.L.Wright@curtin.edu.au
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.
Research, undertaken
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.