3-D GIS; Virtual London and beyond An exploration of the 3-D GIS experience involved in the creation of Virtual London

In this paper, we outline how we have developed a series of technologies to enable detailed interactive 3-D Geographical Information Systems (GIS) based models of cities to be created. Until relatively recently these models have been developed in Computer Aided Design (CAD) software more often then in GIS. One of the main reasons was that '3-D GIS' was often only 2.5-D under closer inspection. This is changing, and by straddling both technologies, and integrating others, we show how these models in turn enable planning information, statistics, pollution levels, sea level rises and much more to be visualised and analysed in the context of the 3-D city model. The client for 'Virtual London' is the Greater London Authority (GLA) and their aim is to develop improved dissemination of planning information, which is explored. We then argue that virtual cities should go well beyond the traditional conceptions of 3-D GIS and CAD into virtual worlds and online design. But we also urge caution in pushing the digital message too far, showing how more conventional tangible media is always necessary in rooting such models in more realistic and familiar representations.