一种改进的城市建筑用地信息提取方法及在广州地区的应用

An Improved Method to Extract Building Land Information and the Application in Guangzhou

对常规的NDBI指数提取城市建筑用地信息的方法进行了改进.在提取NDBI、NDVI和MDWI等3个指数的基础上,分析了建筑用地、植被和水体在这3个指数上的分布规律,找出提取城市建筑用地的最优指数组合方式,进而获取全新的有效的NDBI信息.此外,利用2010年广州地区的ALOS数据进行了城市建筑用地信息提取结果的精度校验,显示整体精度较好,尤其是对高密度城市建筑信息提取更加有效,其精度达到89%.所构建的方法提高了单纯依靠NDBI指数获取城市建筑用地信息的准确性.最后,采用该方法获取了广州市近20年(1990—2010)的城市建筑用地面积,并分析了其城市空间扩展趋势.结果表明,改进的城市建筑信息提取方法是可行的,可以获取更可靠和准确的数据;20年间广州市NDBI平均值增加了0.15,建筑用地面积增长了220%.

A new improved approach is built to obtain the information of building land, which is based on NDBI, a popular method in extracting building land information. Based on extracting the indexes of NDBI/NDVI/MDWI, the information of urban building land can be accurately extracted and the data of these indexes are contrasted. We analyzed the distribution discipline of building land, vegetable and water land in order to find these three indexes association pattern in order to find the best building land pattern on these indexes. Moreover, this paper gives an accuracy assessment using ALOS data of 2010. The results of accuracy assessment show this new method is satisfied for obtaining NDBI, the accuracy is up to 89% for high-density urban pixels. One the other hand, the NDBI infor- mation （1990＆2010） of Guangzhou is extracted using this new method, and the trend of urban spatial expanding is analyzed and discussed. The results are shown as followed： The improved method is effective to extracting the building land. Among the 20 years, the mean value of NDBI increases 0.15 and the area is increasing 220% from 192 km2 to 617 km2.