Bulletin of Surveying and Mapping ›› 2023, Vol. 0 ›› Issue (6): 44-49.doi: 10.13474/j.cnki.11-2246.2023.0166

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Analyzing the spatio-temporal distribution of Eichhornia crassipes based on Sentinel-2 remote sensing

WANG Dongmei1, WU Yongfeng1, SHI Yifan1, LIANG Wenguang1, WANG Yihong1, PAN Siyuan2   

  1. 1. Jiangsu Provincial Institute of Water Conservancy Sciences, Nanjing 210017, China;
    2. School of Agricultural Science and Engineering, Hohai University, Nanjing 210024, China
  • Received:2022-07-28 Published:2023-07-05

Abstract: The large-scale outbreak of Eichhornia crassipes dramatically influence river and lake flood control, water supply security, and water ecology. In this study, the Lixia River area of Jiangsu province is chosen as the research area. We applied the Sentinel-2 image data to filter the optimal classification method of Eichhornia crassipes by compare and analyze the classification accuracy of three machine learning algorithms. Then, analysis the inter-annual spatio-temporal (2017—2021) characteristics and their spreading trends of Eichhornia crassipes by inversion of remote sensing data. The results showed that, the classification performance based on support vector machine (SVM) (overall accuracy is 84.81%~94.30%, Kappa coefficient is 0.70~0.89) is better than neural network (NN) and random forest (RF), The annual outbreak area of Eichhornia crassipes showed a trend of “increase and then decrease” from 2017 to 2021, the outbreak area of Eichhornia crassipes reached its peak in 2019. The outbreak hotspots are mainly located in the junctions of administrative region and dense water networks,such as southern Funing county, central Baoying county, and southern Xinghua city. The average Eichhornia crassipes area during 2017—2021 in the five districts and counties of Xinghua, Baoying, Gaoyou, Jiangdu, and Funing is above 3 km2. Especially, the annual average Eichhornia crassipes outbreak in Xinghua is the most frequent, with an area of 6.85 km2.

Key words: remote sensing, Eichhornia crassipes, Sentinel-2, support vector machine, Lixia River area, spatio-temporal distribution

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