Water spread area is one of the few parameters that can be easily derived using multispectral satellite data. However, due to limitation in land–water boundary pixel delineation and availability of area estimate from simultaneous images of different spatial resolutions, it poses serious challenges for accurate estimation of water spread area. The area estimated from data of different resolutions is not the same owing to many factors like shape and size of the water body and the efficiency of the approaches to delineate land–water boundary pixel. In addition to this, multiple coverage of same water body from sensors of different resolutions will lead to varying water spread area estimates. In order to assess the effect of these factors on water spread area estimate, a study was undertaken to assess the accuracy of water spread area estimate using the field-based measurement and to establish relationship for normalisation of water spread area estimate from different resolution sensors. In this study, water boundary was traced by collecting continuous measurements of location with the help of satellite-based positioning system. The study showed that water spread area estimated through linear spectral unmixing of images from LISS IV, LISS III, AWiFS and MSI sensors resulted in better estimate compared to the index-based method. The error in estimate was less than 5% in all the cases except for AWiFS-based estimate for the smaller water body. The study also concluded that either simple linear regression equation or multiple linear regression equation can be used to normalise the water spread area estimated from different sensors.

中文翻译：

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基于多传感器卫星数据的水传播面积估计精度评估与归一化

水扩散面积是少数可以使用多光谱卫星数据轻松导出的参数之一。然而，由于陆水边界像素划定的限制和不同空间分辨率的同步图像区域估计的可用性，这对水扩散区域的准确估计提出了严峻的挑战。由于水体的形状和大小以及划定陆水边界像素方法的效率等诸多因素，不同分辨率的数据估计的面积并不相同。除此之外，来自不同分辨率的传感器对同一水体的多次覆盖将导致不同的水扩散面积估计。为了评估这些因素对水扩散面积估计的影响，进行了一项研究，以评估使用基于实地的测量的水扩散面积估计的准确性，并建立从不同分辨率传感器估计水扩散面积的标准化关系。在这项研究中，在卫星定位系统的帮助下，通过收集连续的位置测量值来追踪水域边界。研究表明，与基于指数的方法相比，通过对来自 LISS IV、LISS III、AWiFS 和 MSI 传感器的图像进行线性光谱解混估计的水扩散面积得到了更好的估计。除了基于 AWiFS 对较小水体的估计外，所有情况下的估计误差均小于 5%。