Three-dimensional representation of urban built form in a GIS

The Smallworld GIS has been customised to create a means of representing the three-dimensional forms of buildings. To do this, buildings are broken down into 'floor polygons', among whose attributes are floor level and storey height. Data for nondomestic buildings at 3350 addresses in four English towns have been entered into Smallworld, and measurements made of floor areas, roof areas, and exposed wall areas. Floor polygons may be reaggregated into premises, built forms, or by other attributes. Several applications in energy analysis and urban planning are described.