Water Detection in Urban Areas from GF-3.

Xiaoyan Liu,Long Liu,Linjiang Lou,Yun Shao,Qingjun Zhang,Quanhua Zhao

doi:10.3390/s18041299

Abstract

The rapid and accurate detection of urban water is critical for urban management, river detection, and flood disaster assessment. This study is devoted to detecting water by GaoFen-3 (GF-3) Synthetic Aperture Radar (SAR) images with high spatial resolution. There have been no effective solutions that discriminate water and building shadows using a single SAR image in previous research. Inspired by the principle that every shadow has a corresponding building nearby, a new method is proposed in this study, whereby building shadows are removed depending on the correspondence of buildings and their shadows. The proposed method is demonstrated effective and efficient by experimental results on six GF-3 SAR images. The Receiver Operating Characteristic (ROC) curves of the water detection results indicate that the proposed method increases the Probability of Detection (PD) to 98.36% and decreases the Probability of False Alarm (PFA) to 1.91% compared with the thresholding method, where, at the same PFA level, the maximum PD of the thresholding method is 72.62% in all testing samples. The proposed method is capable of removing building shadows and detecting water with high precision in urban areas, which presents the great potential of high-spatial-resolution GF-3 images in terms of water resource management.

Highlights

Urban water, an important factor in an urban ecosystem, is critical for improving urban development, the quality of the living environment, and the stability of the ecosystem [1,2]
To validate the universality of the proposed method, six Synthetic Aperture Radar (SAR) images are chosen by morphology differences, such as spatial resolution, coverage area, polarization mode (HH/VV), shadow direction, and building density
A novel water detection method based on GF-3 datasets is proposed in this study

Summary

Introduction

An important factor in an urban ecosystem, is critical for improving urban development, the quality of the living environment, and the stability of the ecosystem [1,2]. Urban impervious surfaces have taken up greater proportions as urbanization has advanced, which has made urban floods frequent. Accurate and timely water detection is crucial for real-time monitoring, effective prevention, and assessment of flood. With its advantages of spatial and temporal availability and manipulation of data covering large and inaccessible areas within a short time have become facilitate tools in the real-time monitoring of floods. Synthetic Aperture Radar (SAR), with the advantage of not being affected by terrible weather conditions, has become an irreplaceable data source for water information acquisition [3,4]. The Gaofen-3 (GF-3) satellite is China’s first 1 m spatial resolution C band multi-polarization

Methods

Results

Conclusion