【摘要】 城市形态具有分形特征,利用多分形可以从标度的视角揭示其结构演化以及背后的问题。基于1986-2018年遥感数据,计算郑州市域和市辖区建设用地的多分维,并根据谱线分析郑州城市用地近30年的演化特征。结果表明:(1)郑州当前用地已超过理想分维1.7,市域和市辖区的多分维谱线表现异常。市域和市辖区的全局谱线在低密度区快速突破嵌入空间维数2,市辖区的局部分维谱线出现"纽结"现象。(2)郑州市域和市辖区的局部分维谱都表现为单峰左偏,且左端(高密度区)数值高于右端(低密度区),城市生长以向外扩张为主。(3)郑州市域和市辖区的建设用地分维增长符合二次logistic曲线,但曲线的拐点位置不同。市辖区已在2017年达到用地高峰期,用地接近饱和,预留空间不足,而市域预计在2028年达到高峰。根据上述结果,可得出以下结论:(1)郑州城市空间结构在有序发展过程中,存在空间局部的不协调和无序扩展的现象;(2)郑州城市用地的空间集聚过程已经结束,近年表现为对外扩展为主。城市中心区填充过高,而城市边缘无序扩张;(3)郑州市辖区城市用地已经达到极限,如果今后继续扩张,则只能消耗市辖区以外的市域土地。更多还原

【Abstract】 Urban form has fractal characteristics, using multifractals can reveal its structural evolution and problems from the perspective of scaling.Based on remote sensing of construction land from 1986 to 2018, we calculate the multi-fractal dimensions of the construction land at two scales of Zhengzhou all region and its municipal district. According to the multifractal dimension spectrums, we analysis the evolution characteristics of Zhengzhou urban land use in the past 30 years. The main results are as follows: 1)The current fractal dimension of Zhengzhou construction land has exceeded the ideal fractal dimension of 1.7, and the multidimension spectrum curves at two scales of the Zhengzhou all region and the municipal district are abnormal. When q→-∞,the global spectral curves of Zhengzhou all region its municipal district have quickly broken through the two-dimension of embedding space.The "knots" phenomenon appeared in the local spectral curves of Zhengzhou municipal district.2)The peaks of the f(α)curves at two scales of the Zhengzhou all region and the municipal district incline to the left, and the left ends(high-density area) of the curves are higher than the right ends(low-density area), this means fractal growth of urban form is dominated by outward expansion.3) The growth curves of construction land in Zhengzhou all region and the municipal district can be described by the quadratic logistic function, but the inflection points of the different curves are different.Zhengzhou municipal district has reached the peak land use period in 2017.So the land use is nearly saturated, and resulting in insufficient reserved space.However, the construction land of Zhengzhou all region will reach its peak in 2028.Based on these findings, several conclusions can be drawn: 1) During the orderly development of Zhengzhou urban spatial structure, there is a phenomenon of uncoordinated and disorderly expansion of local space.2)The spatial agglomeration process of Zhengzhou urban land has ended.In recent years, the urban space has been dominated by external expansion.The central area of the city is overfilled, and the edges of the city are spreading out of order. 3)The urban land use in Zhengzhou municipal district reached its limit and if it continues to expand in the future, that would consume urban land outside of the municipal district.更多还原