城市空间组织的形成
    Urban spatial structures are shaped by market forces interacting with regulations,primary infrastructure investments and taxes. Urban spatial structures are usually the unintended result of unforeseen consequences of policies and regulations that were designed without any particular spatial concerns. However, different urban spatial organizations perform differently. For instance, some urban shapes are unfavorable to the development of public transport; others tend to increase the efficiency of public transport while reducing residential floor consumption. Urban spatial structures are very resilient and they evolve only very slowly. For this reason, a city’s spatial structure significantly reduces the range of available development options..
    It is not possible to define an optimum city shape because city development objectives change with time. However, it is possible to identify the type of city shape that would be consistent with a specific objective. Typically, mayors are obliged to pursue several objectives at the same time. The choice of the appropriate trade-offs between several often conflicting objectives is a political decisions, not a technical one. This choice is best left to elected officials. Urban planners, however, should constantly
monitor the impact that specific policies may have on city shape. They should be aware of the effect of the most common planning tools – land use regulations, infrastructure investments and taxation – on the spatial organization of a city. They should make sure that the urban shape resulting from their actions will be consistent with the objectives set by elected officials.
    Urban shapes are path dependent. The spatial structure of a large cities evolves very slowly and can evolve only in a few directions. On a large scale, it is never possible to bring back to nature the land that has been already developed. Planners should
therefore have a good understanding of the potentials and liabilities inherent to the current spatial organization of the city in which they work. This paper is demonstrating a number of tools and spatial indicators to apprehend a city’s spatial structure and to help
formulate its potential for different development objectives.