An Across-Country Comparison of the Hierarchical Spatial Structures of Cities

Abstract

This paper investigates the hierarchical structures of 29 selected European countries from the perspective of blocks and natural cities and makes an across-country comparison among the countries. Blocks are minimum cycles consisting of road segments in the road network of a whole country; natural cities are defined as the aggregations of small blocks. We test the size distributions of blocks and natural cities at the country level and find that both exhibit heavy-tailed distributions. The power law distribution of city sizes indicates the presence of the scaling property. Therefore, the cities in a country can be repeatedly grouped into a similar two-tier structure of head and tail via the head/tail division rule. The ascending tiers represent the small, medium, large and mega cities. Accordingly, a simple model is developed to evaluate and cross compare the degree of similarity and stability of the scaling properties and hierarchical structures of cities. Moreover, cities and blocks are the functional units of a country, and the correlation coefficient values between city sizes/number of blocks and economic factors (i.e., gross domestic product and population) are up to 0.87. We further conjecture that the compared results of hierarchies can serve as an indicator to assess a country's economic system.