海口市城市边缘区空间范围的识别研究

Spatial Scope of the Urban-rural Fringe in Haikou

城市边缘区位于城市与乡村之间的过渡交接地带,是城市扩张的前沿,也是城乡建设中最具活力的地区.准确地识别城市边缘区,有助于从城乡对比的角度来衡量城市化程度及其对生态环境的影响,有利于推进城市规划学科的进展.以海口市遥感影像数据为基础,选用不透水面指数评价土地利用程度,然后运用最大熵阈值法进行图像分割,界定海口市城市边缘区内外边界,并对海口市城市边缘区空间范围进行具体识别.最后通过人口统计和归一化植被指数验证识别结果的准确性,并依据识别结果对海口市2009—2017年城市边缘区扩展状况及驱动因素进行分析研究.结果表明,海口城市边缘区扩展变化主要受到自然因素、交通和人口等因子的影响.将不透水面指数与最大熵阈值分割法相结合可以直接从遥感影像中识别出城市边缘区,这是后续对这一特殊区域特征进行研究的基础.对海口城市边缘区扩张研究,有助于促进海口市的城乡协调发展,其对海口市实现城市规划与管理的可持续发展和生态与环境的平衡发展具有重要意义.

The urban-rural fringe is the frontier of urban expansion and the most dynamic area of the city,and which is located in the transition zone between the city and the countryside. The accurate identification of urban fringe is helpful to measure the degree of urbanization,and promote the progress of urban planning. In the report, based on the remote sensing image data in Haikou,the impervious surface index was used to evaluate the degree of land use. Then,the maximum entropy threshold method was used for image segmentation to define the inner and outer boundaries of urban-rural fringe and specifically identify the spatial scope of urban-rural fringe in Haikou. Finally,the demographic and normalized difference vegetation index were used to verify the accuracy of identification results,and based on the identification results,the expansion status and driving factors of Haikou' s urban fringe areas during 2009-2017 were analyzed. The results showed that the expansion of Haikou urban fringe is mainly affected by natural factors,traffic and population. The combination of impermeable water surface index and maximum entropy threshold segmentation method can directly identify urban fringe areas from remote sensing images,which is the basis of subsequent research on this special regional characteristics. These findings are helpful to promote the coordinated development of urban and rural areas in Haikou,and is of great significance to the sustainable development of urban planning and management as well as the balanced development of ecology and environment in Haikou.