基于数据融合的长江经济带城市建成区时空格局研究

Spatial and Temporal Pattern of Urban Built-up Areas in the Yangtze River Economic Belt Based on Data Fusion

在"共抓大保护,不搞大开发"导向下,准确识别长江经济带城市建成区,并揭示其演化规律对于优化流域国土空间格局具有重要意义。基于Landsat数据和夜间灯光数据,构建融合算法提取长江经济带城市建成区,并采用位序-规模、核密度、空间自相关等方法探索了其时空格局特征。结果表明:(1)长江经济带城市规模存在明显的位序-规模分布格局,分形特征显著;(2)建成区规模呈现"东高西低"、"轴线高两端低",建成区密度呈"一个中心,两个次中心"的格局特征;(3)城市由点源聚集增长向轴线式扩张转变,国土空间"T"型增长格局逐渐显现;(4)建成区增长表现出空间集聚特征,区域内三大城市群为主要热点区。研究结果能够为流域国土空间"保护"与"开发"权衡提供定量参考和决策依据。

Under the strategic guidance of "grasping the major protection and no large-scale development", it is of great significance to accurately identify the urban built-up areas of the Yangtze River Economic Belt and reveal its evolution laws for optimizing the spatial pattern of the river basin. Based on Landsat data and night lighting data, this paper constructs a fusion algorithm to extract urban built-up areas of the Yangtze River Economic Belt, and uses fractal theory, core density, spatial autocorrelation and other technical methods to reveal the evolution pattern and spatial correlation of the urban built-up areas. Results show that:(1) The overall pattern identification shows that urban scale of the Yangtze River Economic Belt shows an obvious rank-size distribution pattern, which has significant fractal features.(2) The scale of urban built-up areas in the Yangtze River Economic Belt shows regional differences, precisely, they take Yangtze River as the axis, some are high in the east while the others are low in the west. Besides, some in the central axis are higher than those in the both sides. The density of built-up areas is spatially distributed as one central spot with two sub-central spots.(3) We find that the urban scale of the Yangtze River Economic Belt expanded gradually, and the expanding formation transformed from the pole to the axis, and overall shows a "T" growth pattern.(4) By the comparison of different regions, we find that the fast-growing areas are mainly distributed in Yangtze River Delta city group, Chengdu-Chongqing city group and Wuhan city group. Our results can provide reference and decision-making proof for the tradeoff between "protection" and "development" of the river basin.