Abstract: Agricultural resources are in good condition in Hetao Irrigated Area,suitable for the growth of a variety of crops,and the plots are relatively fragmented.A remote sensing technology can be used to accurately identify crop types so that agricultural resources in this area can be investigated and the agricultural conditions can be evaluated.Using 9 phases of GF-1/WFV data in the period from April 2017 to October 2017,this paper combined the method of transforming the field sample points into sense areas to calculate and analyze the time series NDVI values and variation characteristics of spring wheat,corn,helianthus and vegetable in the whole growth stage in the study area,and thenthe decision tree classification model based on threshold segmentation was constructed to identify and classify the above five crops in this area.Ten verification quadrangles were selected from RapidEye data with a resolution of 5 m,the crops in the quadrangle were visually interpreted,and the classification results of the decision tree were verified with the interpretation results and expressed with confusion matrix.The results showed that identification accuracies of spring wheat,corn,sunflowers,zucchini,and tomatoes were 88.86%,62.44%,87.29% and 65.78%,respectively,while the overall accuracy reached 76.29% and the Kappa coefficient was 0.652 9.It can be seen that by analyzing the time series data based on GF-1/WFV NDVI,large crops in mesoscale can be identified more accurately.This method is suitable for the application and research of remote sensing in agricultural resource survey.

Key words: Crop identification, GF-1/WFV, NDVI, Decision tree, Spectral information