基于引力势力范围的郑州城市多中心空间形态识别

Recognition of Zhengzhou urban multi-center spatial form based on influence sphere of gravity

识别和分析城市多中心结构的空间形态,对优化城市空间结构具有重要意义。对引力模型的多中心综合实力参数和距离参数测定方法进行优化,首先将能够反映居民对空间结构感知体验的空间句法可达性,与人口经济和社会活动空间分布结合构建评价体系,定量计算多中心综合实力;然后将能够表达居民出行轨迹空间特征和偏好规律的词向量相关性,作为距离参数引入引力模型;最后计算引力强度并划分势力范围,对多中心发展目标的现实演化状态进行分析和评价。通过对比实验发现:优化引力模型与传统引力模型分析的势力范围存在一定差异,经空间统计和实地调查验证,优化模型对多源数据的运用更充分,考虑的因素更全面,其空间形态分析结果较为准确;从识别与规划多中心势力范围差异看,二者在郑州市核心城区的势力范围较为相似,均为早期规划或自然演化形成的已建成多中心,而部分外围多中心的识别与规划位置不同,空间形态差异明显,为未建成多中心,还远未形成其应有的分散疏解作用。

It is of great significance to identify and analyze the spatial form of urban polycentric structures for the optimization of urban spatial structure. In this paper, the measurement methods of the comprehensive strength parameters and the distance parameters of the gravity model in multi-centers are optimized. Firstly, the accessibility of the spatial syntax which can reflect the perceptions of the residents on spatial structures is combined with the spatial distribution of the population, economic and social activities to build an evaluation system and quantitatively calculate the comprehensive strength of the multi-centers. Then, the word vector correlations, which can express the spatial characteristics and preference rules of the travel trajectory of the residents, are introduced into the gravity model as a distance parameter. Finally, the gravity strength is calculated and the influence sphere is divided to analyze and evaluate the realistic evolution state of the multi-center development goals.Furthermore, comparative experiments revealed that there are some differences in the influence sphere between the optimized gravity model and the traditional gravity model. Verified by spatial statistics and field investigation, the modified model optimizes the use of multi-source data and considers more comprehensive factors, thus providing more accurate spatial morphology analysis results. Findings revealed that there are differences between the spheres of influence of the identified and planned multi-centers, and their spheres of influence in the core urban area of Zhengzhou are very similar. And these centers are multi-centers previously formed through planning or natural evolution. Additionally, the location and spatial form of some peripheral identified multi-centers differ significantly from those of the planned centers.These multi-centers have not been built yet. Hence, they do not satisfy the needs of dispersing and relieving urban pressure.