Optical VGI yield estimates were validated with CropWatN crop model yield estimates using SPOT and NOAA data (mean R 2 0.71, RMSE 436 kg/ha) and with composite SAR/ASAR and NDVI models (mean R 2 0.61, RMSE 402 kg/ha) using both reflectance and backscattering data. CropWatN and Composite SAR/ASAR & NDVI model mean yields were 4,754/4,170 kg/ha for wheat, 4,192/3,848 kg/ha for barley and 4,992/2,935 kg/ha for oats.