Quantifying Sub-Pixel Surface Water Coverage in Urban Environments Using Low-Albedo Fraction from Landsat ImageryReportar como inadecuado


Quantifying Sub-Pixel Surface Water Coverage in Urban Environments Using Low-Albedo Fraction from Landsat Imagery


Quantifying Sub-Pixel Surface Water Coverage in Urban Environments Using Low-Albedo Fraction from Landsat Imagery - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

1

Department of Geography and Spatial Information Techniques, 818 Fenghua Road, Ningbo University, Ningbo 315211, China

2

State Key Lab of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China

3

School of Computer, Wuhan University, Wuhan 430079, China





*

Author to whom correspondence should be addressed.



Academic Editors: Qi Wang, Nicolas H. Younan, Carlos López-Martínez, Magaly Koch and Prasad S. Thenkabail

Abstract The problem of mixed pixels negatively affects the delineation of accurate surface water in Landsat Imagery. Linear spectral unmixing has been demonstrated to be a powerful technique for extracting surface materials at a sub-pixel scale. Therefore, in this paper, we propose an innovative low albedo fraction LAF method based on the idea of unconstrained linear spectral unmixing. The LAF stands on the -High Albedo-Low Albedo-Vegetation- model of spectral unmixing analysis in urban environments, and investigates the urban surface water extraction problem with the low albedo fraction map. Three experiments are carefully designed using Landsat TM-ETM+ images on the three metropolises of Wuhan, Shanghai, and Guangzhou in China, and per-pixel and sub-pixel accuracies are estimated. The results are compared against extraction accuracies from three popular water extraction methods including the normalized difference water index NDWI, modified normalized difference water index MNDWI, and automated water extraction index AWEI. Experimental results show that LAF achieves a better accuracy when extracting urban surface water than both MNDWI and AWEI do, especially in boundary mixed pixels. Moreover, the LAF has the smallest threshold variations among the three methods, and the fraction threshold of 1 is a proper choice for LAF to obtain good extraction results. Therefore, the LAF is a promising approach for extracting urban surface water coverage. View Full-Text

Keywords: urban surface water extraction; threshold stability; sub-pixel; linear spectral unmixing; Landsat imagery urban surface water extraction; threshold stability; sub-pixel; linear spectral unmixing; Landsat imagery





Autor: Weiwei Sun 1,2,* , Bo Du 3 and Shaolong Xiong 2

Fuente: http://mdpi.com/



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