基于时空大数据的北京城市功能混合评估方法及规划策略

 城市功能混合是提升城市效率和活力的重要手段，也是现代城市规划的重要原则。提出了一种基于多源时空大数据的城市功能混合评估新方法，该方法借鉴了TF-IDF算法和信息熵算法，不仅考虑各类城市功能的空间布局结构，而且反映了其实际使用特征，从而将城市功能的供给侧与需求侧特征结合起来。基于这一方法，对北京六环以内地区的城市功能混合进行计算。结果表明，城市功能混合现象极为普遍，应视为城市规划和管理的一项基本原则；从空间特征上看，功能混合密度符合距离衰减特征，体现了空间区位与城市中心结构对城市功能混合的显著影响。在此基础上，进一步探讨了不同主导功能的用地中，各类城市功能混合的配比关系和空间特征。最后，面向城市规划和管理，提出了提升城市功能混合、加强城市精细化治理水平的可行建议。

The evaluation method and planning strategies of urban function mix of Beijing based on spatiotemporal big data

The urban function mix is a key element in the scheme of improving the efficiency and the vitality. Also, it serves as a significant principle in the modern urban planning. Therefore, the determination of the function mix level of a city and the adoption of effective optimization strategies are essential for the construction of human-oriented cities. A new approach is proposed in this paper for the evaluation of the urban function mix based on the multi-source geospatial big data by combining the spatial layout and the actual condition of the utilization together, to incorporate the characteristics of both supply and demand of urban functions. The method is then applied to explore the spatial characteristics and factors of the urban function mix of the region inside the sixth ring of Beijing. The results suggest that urban function is a common phenomenon in Beijing, and it should be considered as a fundamental principle in the urban planning and management. From the perspective of spatial characteristics, the density of the urban function mix follows a distance decay law, which reflects the significant influence of the location and the polycentric structure. Furthermore, the relationship between the mix ratio and the spatial pattern of urban functions in blocks, dominated by different functions, is discussed. Finally, practical suggestions are made to optimize the urban function mix and to improve the urban fine governance for urban planners and decision makers.