Monitoring of Rice Irrigation Area Based on GF-1 Data and Spectral Matching Technology- A Case Study of Chuanhang Irrigation Area in Suqian City

China is the world’s largest rice producer and consumer. Accurate identification of rice planting and irrigation area is of great significance to China’s food security. Based on GF-1 multispectral data, spectral matching and OTSU algorithm were used to monitor the rice irrigation area in Chuanhang Irrigation Area from 2016 to 2020. The accuracy was verified by confusion matrix. The overall accuracy was 98.1691%, 91.8706%, 95.2451%, 93.0604%, 91.9697%, respectively. The Kappa coefficients were 0.9541, 0.7898, 0.8777, 0.8330 and 0.7824, respectively, which proved that this method was suitable for rice irrigation area extraction based on high spatial resolution remote sensing data, and could provide technical support for rice irrigation area monitoring in irrigated areas.