Abstract:

On the basis of the urban system of hierarchy, cities may be divided to megalopolis, metropolis, large-city, middle-city, small-city and town. The fractal structure is characteristic of the urban system in which there is a lattice-distribution of same grad cities. In the parallelogram lattice there are two directions parallel to tectonics lines in the region, respectively. Taking megalopolis and small,medium,large cities as an example,this paper analyzes the city distribution of lattice.It regards that in a region,in addition to the symmetry of lattice,there may also be a higher symmetric form.The city distribution and complexity system have an important significance for the regional development and urbanization,and the mathematical model should be established accordingly.

Key words: city, fractal structure, hierarchy system, symmetry, lattice-distribution