Numerical Model of Street Morphogensis – MoNuMoVI

The project is to build a numerical model for the street development during urban growth. Urban growth is a very complex subject, implying numerous effects from different fields (including human), with an increasing size of data, but we want to catch it from the street aspect. Streets are indeed an objective and visible result of the urbanization that summarizes its particular structure and organization. In the same time, this streets organization constrains and directs the possible exchanges in the city, and thus its life and growth. The underlying idea of this project is that the streets are not only representative of the city functioning, but also constrain a big part of the future development.

To do so we extend a pre-existing numerical model, both analyzing the essential information from the existent streets, and computing the possible new streets. It aims at reproducing the complexity of a city, as the different types of neighborhoods, including the effect of pre-existing constraints such as access roads, rivers and topography, but also large social events such as the construction of protecting walls, or surrounding highways, or global internal reorganizations.

Such numerical models will be validated by a analyzing their results and comparing it with the analysis of actual streets patterns, both the local type of organization and the global efficiency of a burrow or a city. These analyzing tools are thus essential. We will further compare quantitatively and in fine details the simulation results of growth with the data that we will collect from the succession of historical maps (to be inserted modern Geographic Information Systems data).

It is also important for us that such models will be validated directly by the social actors, by submitting their results to the judgment of the actual town planners. For this we will develop simple and intuitive tools of visualization, and a software platform that the town planners could use with their own set of data. Such tool could be provided on-line, allowing also citizens as well as decision makers to use them to nourish possible discussions on the effect of planned modifications (such as new streets or street closing). Such development can be either a toolbox added to current GIS software, or a free web-site allowing to compute the various analyses from people’s imported data. This will also involve the development of new functionalities for GIS, as they are not turned for the moment to any time evolution representation and analysis.

For the use of decision makers, the urban evolution model would allow long-range planning, guiding them toward the most natural growth. The development of these numerical tools is important now in view of the accelerating urban growth, and in particular the sustainable development problem. Theses numerical tools would help to define the best politics to built a sustainable expanding city.