Patterns for building Utility Data Models

Patterns in GIS Software Components
The goal of the modeler is to solve the riddle of contrasting representations by creating a data model that unifies the network, cartographic, and tabular views of a utilit y system. A central instrument of the data modeler is the intrinsic data model exposed by the native GIS. Modern object-oriented GIS software offers several new facets that enables the modeler to realize the integration of the disparate representations of objects. Newly engineered GIS software offers:

Implementation upon commercial off-the-shelf relational database management systems of the customer’s choice. GIS software extends the DBMS with support for long transactions and versions, spatial data types and operators, and map display and query.
A soflware component-based data model which is extensible by configuration management and object-oriented programming techniques of inheritance and encapsulation.
Customization through standard visual programming environments such as Visual Basic, Delphi, or Visual C++.
Improved native support for linear networks that contain map features with relationships to one or several virtual network elements.

Linear networks
A common problem to any domain based upon linear networks is that the cartographic features do not correspond precisely to elements of the implicit network.

Consider a transportation network. It includes features such as railroads, highways, rivers, and airline routes. Some of these network features allow transport in both directions while others constraint transport to one direction. An airline route is an interesting object: It certainly should be modeled within a network, but it isn’t properly a map feature.

Furthermore, utility data models contain complex objects where one geographic feature represents multiple elements, such as cable pairs or phases of power. These requirements lead to a GIS data model that supports considerable flexibility in feature representation and network modeling.