A Comparison of Satellite-Based Estimates of Urban Agglomeration Size for the Accra Area
A Comparison of Satellite-Based Estimates of Urban Agglomeration Size for the Accra Area
复制标题
DOI：
10.3390/ijgi9020079
复制
发表时间：
2020-01
期刊：
影响因子：
--
通讯作者：
L. Møller-Jensen;A. Allotey;R. Kofie;P. Yankson
中科院分区：
文献类型：
--
作者：
L. Møller-Jensen;A. Allotey;R. Kofie;P. Yankson
关于城市地区扩展的数据对于分析增长动态和支持运输和服务提供的规划十分重要。事实证明，卫星遥感极为有用，特别是在空间快速增长的城市。然而，不同的卫星制图方法可能会在城市分类和划定方面产生不同的结果，从而往往使直接比较产生误导。本研究分析了四个不同的基于卫星的城市土地覆盖研究在阿克拉，加纳，并提出了一个新的土地覆盖地图的基础上分割哨兵-2图像的视觉解释。的方法和结果，以及“城市”的基本定义，进行了比较和讨论。一种方法是专门确定具有人造不透水表面的区域，如道路和建筑物，作为城市范围的代理。其他方法旨在确定更广泛的土地覆盖类型，包括作为混合城市结构一部分的绿色空间。在根据城市化程度对发展中的城市边缘地区进行分类的方式以及用于界定城市群的距离阈值方面，还发现了进一步的差异。对于最新的地图，我们确定的差异，在测量的大小的阿克拉团聚几乎100%。
Data on the extension of urban areas are important for analyzing growth dynamics and to support the planning of transport and service provision. Satellite-based remote sensing has proven extremely useful, especially in cities that experience fast spatial growth. Different approaches to satellite-based mapping may, however, produce different results concerning urban categorization and delineation, often making direct comparison misleading. This study analyses four different satellite-based studies of urban land cover in Accra, Ghana and presents a new land cover map based on visual interpretation of segmented Sentinel-2 imagery. The methods and results, as well as the underlying definition of “urban”, are compared and discussed. One method identifies exclusively areas with man-made, impervious surfaces, such as roads and buildings, as proxies for urban extent. Other methods aim to identify a broader set of land cover types, including green spaces, which are treated as part of the mixed urban fabric. Further differences are found in the way urban fringe areas under development are classified depending on their degree of urbanization, and in the distance threshold values used for defining the urban agglomeration. For the most recent maps we identify a difference in the measured size of the Accra agglomeration of almost 100%.