Preliminary Evaluation of Gaofen-3 Quad-Polarized SAR Imagery for Longbao Protected Plateau Wetland Reserve

Abstract

The Chinese Gaofen-3 (GF-3) synthetic aperture radar (SAR) satellite launched by the China Academy of Space Technology is under continuous operating mode at C-band since September 2016. The main objective of this study was to present a preliminary evaluation of GF-3 quad-polarized SAR imagery for protected wetland classification. Four scenes of GF-3 quad-polarized SAR imageries were collected in this study and analyzed systematically. Besides, the GF-2 optical imagery and in situ survey results were also collocated as reference data. It was verified that the polarized features including double bounce scattering component Pdbl, odd bounce scattering component Podd, and volume scattering component Pvol from Freeman decomposition algorithm were well applied in distinguishing typical coverage of Longbao protected plateau wetland. In consideration of robustness of classifier, the method of Maximum Likelihood Classification was investigated for classification based on selected polarized features. The Kappa coefficient and overall accuracy of classification mapping are 0.75 and 82.16%, respectively, which revealed that the GF-3 quad-polarized SAR can provide a satisfying mapping for classification of Longbao protected plateau wetland.