高分二号(GF-2)影像的高空间分辨率有助于获得更为准确的水体分布信息。针对现有水体指数难以应对复杂环境、高空间分辨率的遥感影像水体提取时易出现“椒盐”现象的问题,基于GF-2影像进行了水体指数的构建及验证。首先,通过分析各地表...高分二号(GF-2)影像的高空间分辨率有助于获得更为准确的水体分布信息。针对现有水体指数难以应对复杂环境、高空间分辨率的遥感影像水体提取时易出现“椒盐”现象的问题,基于GF-2影像进行了水体指数的构建及验证。首先,通过分析各地表覆盖物的波谱信息,构建了一种综合水体指数(comprehensive water index,CWI),并进行精度验证;其次,通过图像分割结合水体指数进行水体提取并进行精度验证;然后,为了充分利用光谱信息和发挥分类器的优势,将分割后同质对象的光谱信息与水体指数组合作为分类器的输入数据,进行水体提取并进行精度验证;最后,验证综合水体指数在WorldView-2影像和GF-1影像的适用性。经过研究可知:①新构建的综合水体指数在进行水体提取时,能够有效抑制阴影、建筑物、道路、植被、裸土等地表覆盖的影响,精度明显提高;②通过图像分割结合水体指数提取水体信息能有效抑制“椒盐”现象的产生;③分类器结合水体指数能有效提高水体提取精度;④综合水体指数同样适用WorldView-2影像和GF-1影像。综上分析,综合水体指数能够有效地提取水体信息,可用于河流、湖泊的提取和更新,池塘养殖面积的调查等,是一种高精度的水体提取方法。展开更多
Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central ...Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central China has become a serious problem for its development. In this study, the surface water quality was evalu- ated using Nemerow Comprehensive Pollution Index （NCPI）, and the change trend was calculated using methods of Mann-Kendall test and Sen＇s slope estimator, based on the monitoring data from 1998 to 2008. The results show that the NCP1 ranged from 3 to 50 in 70% of the monitoring cases, implying that most rivers were seriously polluted. However, this serious polltuon is expected to be gradually improved, as the concentration of water pollutants and NCPI declined significantly in most rivers. Water pollution in reservoirs was much lower than rivers, and the NCPI in the three monitored reservoirs was lower than 3 in most years, and shows a downward trend. Although the surface water quality was gradually improved, great efforts are still needed to enhance the protection and improvement of surface water environment.展开更多
文摘高分二号(GF-2)影像的高空间分辨率有助于获得更为准确的水体分布信息。针对现有水体指数难以应对复杂环境、高空间分辨率的遥感影像水体提取时易出现“椒盐”现象的问题,基于GF-2影像进行了水体指数的构建及验证。首先,通过分析各地表覆盖物的波谱信息,构建了一种综合水体指数(comprehensive water index,CWI),并进行精度验证;其次,通过图像分割结合水体指数进行水体提取并进行精度验证;然后,为了充分利用光谱信息和发挥分类器的优势,将分割后同质对象的光谱信息与水体指数组合作为分类器的输入数据,进行水体提取并进行精度验证;最后,验证综合水体指数在WorldView-2影像和GF-1影像的适用性。经过研究可知:①新构建的综合水体指数在进行水体提取时,能够有效抑制阴影、建筑物、道路、植被、裸土等地表覆盖的影响,精度明显提高;②通过图像分割结合水体指数提取水体信息能有效抑制“椒盐”现象的产生;③分类器结合水体指数能有效提高水体提取精度;④综合水体指数同样适用WorldView-2影像和GF-1影像。综上分析,综合水体指数能够有效地提取水体信息,可用于河流、湖泊的提取和更新,池塘养殖面积的调查等,是一种高精度的水体提取方法。
文摘Water pollution is one of the major environmental prob- lems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central China has become a serious problem for its development. In this study, the surface water quality was evalu- ated using Nemerow Comprehensive Pollution Index （NCPI）, and the change trend was calculated using methods of Mann-Kendall test and Sen＇s slope estimator, based on the monitoring data from 1998 to 2008. The results show that the NCP1 ranged from 3 to 50 in 70% of the monitoring cases, implying that most rivers were seriously polluted. However, this serious polltuon is expected to be gradually improved, as the concentration of water pollutants and NCPI declined significantly in most rivers. Water pollution in reservoirs was much lower than rivers, and the NCPI in the three monitored reservoirs was lower than 3 in most years, and shows a downward trend. Although the surface water quality was gradually improved, great efforts are still needed to enhance the protection and improvement of surface water environment.
