Wetland mapping and wetland temporal dynamic analysis in the Nanjishan wetland using Gaofen One data

摘要

The Nanjishan Wetland National Nature Reserve (NWNNR) encompasses the southern part of Poyang Lake and is the largest wetland reserve on Poyang Lake. Few systematic and specific studies to map the Nanjishan wetland and assess wetland changes have been conducted. Therefore, this paper discusses methods of wetland classification mapping and an analysis of wetland seasonal changes in the flood and dry seasons in the Nanjishan wetland, providing a qualitative description of the causes of seasonal wetland changes. In this paper, two remote sensing images (Gaofen One [GF-1]) typical of the flood and dry seasons were collected and preprocessed. Decision trees (DCs) are computationally fast, make no statistical assumptions and can handle data that are represented on different measurement scales. In this study, a decision tree was proposed to extract wetlands from GF-1 images of the Nanjishan wetland. The decision tree classification (DTC) method yielded the highest overall accuracies, which were 96.12% and 92.76%. The change detection results indicated that the water, marsh and low-density meadow areas changed significantly in conjunction with remarkable transformations between the other wetland cover types. The results discussed in this paper will provide fundamental information to local governments for the protection and restoration of the ecosystem of the Nanjishan wetland.