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Abstract:
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A GIS has been designed with limited Functionalities; but with a novel approach in
Aits design. The spatial data model adopted in the design of KBGIS is the unlinked
vector model. Each map entity is encoded separately in vector fonn, without referencing
any of its neighbouring entities. Spatial relations, in other words, are not encoded. This
approach is adequate for routine analysis of geographic data represented on a planar map,
and their display (Pages 105-106). Even though spatial relations are not encoded
explicitly, they can be extracted through the specially designed queries.
This work was undertaken as an experiment to study the feasibility of developing a
GIS using a knowledge base in place of a relational database. The source of input spatial
data was accurate sheet maps that were manually digitised. Each identifiable geographic
primitive was represented as a distinct object, with its spatial properties and attributes
defined. Composite spatial objects, made up of primitive objects, were formulated, based
on production rules defining such compositions. The facts and rules were then organised
into a production system, using OPS5 |