西北中小城市建设用地增长的特征、动因及其分类引导

Characteristics,motivation and classification guidance of urban construction land growth of the small and medium-sized cities in Northwest China

从我国西北地理分区层面研究中小城市用地增长特征和动力机制是新时期城市高质量管控的突破口,也是促进这一区域形成协调发展新格局的关键点。通过解译近15 a来西北中小城市遥感影像和大比例尺辅助数据,首先运用年均增长速率、质心迁移速率、拓扑关系和分形维数方法,分别测算建设用地增长的速率、方向性、方式和边界形态特征,以认识其增长的时间离散、空间差异及聚集程度。据此提出不同特征城市增长的动因:重点产业或主体功能的植入促使城市中高速外延型增长,城市边缘区土地权属干扰导致低速率弱方向+外延型非规整增生,新城缓慢而有序的建设促使城市低速率外延规整化增长,城市片区之间用地的填补式开发促使低速率弱方向填充型增长。在此基础上,提出不同增长动因城市的分类引导策略,为今后城市用地规划管控决策提供建议。

The research on the characteristics and dynamic mechanism of the construction land use growth in the small and medium-sized cities is the breakthrough point of city’s management and control of high quality in the new era from the geographical zone perspective in Northwest China.It is also the key to promote a new pattern of coordinated development in the corresponding regions.Based on the interpretation of the remotely sensed images and large scale supplementary data of the small and medium-sized cities in Northwest China over the past 15 years,the time discreteness,the spatial difference and the aggregation extent of the growth were analyzed using the method of annual growth rate,centroid migration rate,topological relation and fractal dimension to measure the rate,direction,pattern and boundary shape of the urban construction land use growth.Then,the study investigated the growth motivations and summarized as follows: the implantation of key industry or main function promotes the urban extrorse growth with medium or high-speed epitaxial growth;the disturbance of land ownership in urban fringes leads to a directionless irregular growth with low speed and yet this irregularity was gradually forced to become regularized by the slow and well-organized construction in the fringes;the fill-up type of development of the land use between urban districts impels this padding alike type of growth with low-speed and weak-direction.Based on the findings,this paper puts forward the classification and guidance strategies for the cities with different growth driving forces in their future urban land use planning and control decisions.