For some strange reason, the geo-community has something of a hang up over dimensionality. Perhaps the reasons for this are not so strange given the deep roots of GIS in the world of mapping. Nonetheless the idea that there is a some sort of special barrier to cross when we move from the world of 2D or so called 2.5D to 3D seems rather widespread.
The “strangeness” of 3D is even more amazing if one considers that about 50% of the total world population now live in urban areas and that something like 160,000 people PER DAY are moving from rural areas to urban ones. This means that each day we need to expand the transportation, housing and provisioning systems of the world’s cities to accommodate this huge influx of people. This move to urbanization clearly drives the development of new infrastructure and in a manner out of proportion to the growth in population.
This rapid urbanization of the entire planet demands a new and holistic approach to the built environment. We can no longer consider buildings in isolation from one another, or from the transportation and provisioning systems that support them. We must move to having permanent, evolving and completely integrated models of our cities, which can form the basis for urban planning, operational decision making, and response to everything from terrorist attacks to threats to environmental security.
I do not see this as some extension or new phase of the GeoWeb. It simply is the GeoWeb. I point this out, only so that no one will think that somehow the GeoWeb is confined to, or driven by a 2D world view. It is not! The issues of data aggregation and sharing are independent of dimension. The challenges faced by our cities simply make solving these problems more urgent and more vital.