This International Standard defines a feature-centred rule-based portrayal mechanism. Instances of
features are portrayed based on rules, which make use of geometry and attribute information. The
relationship between the feature instances, attributes and the underlying spatial geometry is specified
in an application schema according to ISO 19109.
Portrayal information is needed to portray a dataset containing geographic data. The portrayal
information is handled as portrayal specifications applied according to specific portrayal rules
(Clause 8). The portrayal mechanism makes it possible to portray the same dataset in different ways