基于城市斑块的空间城市人口潜能模拟——以京津冀为例

城市潜能是城市空间相互作用的一个量化指标,用以表征区域内任一地点所受到的周围所有城市的作用合力。以城市人口规模作为潜能计算指标的城市潜能即为城市人口潜能。由于在地理信息系统中通常以点代表城市的空间位置,以点的属性字段存储城市人口数量,因此,城市人口潜能模拟最便捷的方法是建立基于城市点源数据的空间分析模型,但这种方法存在明显不足:(1)国家基础地理信息数据库中的城市点位经纬度绝大多数与现实中的城市人口质心不吻合;(2)多数城市通常都由空间上相互分离的多个城市用地斑块构成,城市辖区内部的斑块与斑块之间也存在相互作用。本文通过将独立的城市斑块作为基本空间分析单元来设计基于城市人口潜能的模拟技术方案,提出了斑块分层方法,构建了京津冀时间耗费栅格面,通过python建模技术,在ArcGIS平台上实现了对京津冀城市人口潜能的精细化数值模拟。

Simulation of Spatial Urban Population Potential Based on Urban Patches ： Taking Beijing-Tianjin-Hebei Region as an Example

Urban potential is a quantitative indicator to measure the urban spatial interaction. It is used to de- scribe the interaction force exerted to any place in the region, while taking into consideration that the interaction force is produced jointly by all the other surrounding cities. Urban population potential is the potential that is measured and indicated by urban population. GIS usually uses points to represent the spatial locations of cities and uses the point attribute field to store their urban population information. Therefore, the most convenient way to simulate urban population potential is to build a spatial analysis model based on the relevant point data. Obvi- ously, this method has some disadvantages： on one hand, urban point data represented by latitude-longitude pat- tern in national fundamental geographic information datasets does not coincide with the urban population cen- troids in reality; on the other hand, most cities are usually composed of a variety of mutually separated urban land-use patches and these patches interact with each other within their urban precincts. To overcome the impacts of these disadvantages, this study has designed a simulation technology solution of urban population potential based on urban land-use patches. It takes the independent urban patches as the basic spatial analysis units and propose a method to divide grades for those urban patches in Beijing-Tianjin-Hebei region. Then, a time-consum- ing grid surface of Beijing-Tianjin-Hebei region is established. The numerical simulation of the urban population potential in Beijing-Tianjin-Hebei region is realized by making use of ArcGIS platform and modeling techniques of python accordingly. The method based on urban land-use patches could overcome the deficiency that the ur- ban points do not coincide with urban population centroids in reality and it could reflect the spatial interactions of urban interior patches. Moreover, the simulation of urban population potential has further satisfied the require- ments toward refinement.