Time shift evaluation to improve yield map quality

Quality data sets are essential for precision fanning. Yield monitor data s ets have to be processed to coordinate yield information with the proper ge ographic references because of time delays involved with threshing the crop and receiving he yield information. The time shift needed to account for t hese delays was shown to vary from 8 to 14 s. Held data generated by three different combines in corn and soybeans were tested with a range of time sh ifts. Conventional yield maps were also processed to evaluate the results. A value termed surface area ratio (SAR) was developed to determine the best time shift for the data. SAR is the ratio of the upper surface area of a 3 -D yield map to the projected area of that yield map. All of the data sets produced a localized minimum value of SAR at a time shift that also produce d a conventional yield map with the best visual interpretation. The time sh ifts, as determined by the minimum SAR, varied by combine. SAR appears to b e a valid method for determining the correct time shift for yield sensing s ystems.