A smart city is an urban area that uses different types of electronic data collection sensors to supply information used to manage assets and resources efficiently. But before that can happen we need to know what assets and resources our urban environments contain and model them accurately. Enter PIM (Precinct Information Modelling).
A PIM is a comprehensive 3D digital database model of a precinct that contains all the Information needed to support planning, design, development, construction, management, operation, use and retro-fitting of urban precincts.
Since the physical world is made up of objects, generally constructed or adapted by us for our convenience, it is natural to construct a PIM as a collection of objects (building, bridge, road, park, etc.) and then associate data or information with those objects. Importantly, that data could be drawn from all kinds of existing sources through live database links: usage data, planning data, utility data, social data, product performance data, etc.
Note that many of those objects can be broken down as an aggregation of smaller objects, so a road is made up of footpaths, kerbs, gutters, traffic lanes, and those objects can be further broken down into the parts that are used to construct them (materials and structures). Furthermore, a road is actually part of a larger network of roads forming a transport system, which in itself is an object.