Winter wheat yield estimating based on 3S integration and field measurement

Integration technology of GIS, RS and GPS were used to estimate yield of winter wheat in Yuncheng of Shanxi. The results showed that the last ten days of March were the optimum time for area estimation of winter wheat. The first and second ten days of April were the best period for estimating yield. It was more effective for information of winter wheat area extraction with TM data and information of green level extraction with AVHRR. According to the amount of NDVI, winter wheat was divided into 3 types and each type of wheat had significant different yield in different region. After analyzing the features of physical geography and key data of meteorology, a synthesis model was established based on the main factors of NDVI, temperature, and humidity.