Yield Mapping Based on Moving Butterfly Neighborhoods and the Optimization of their length and width by Comparing with Yield Data from a Combine Harvester

摘要

Every value of the yield map is determined by robust fitting of a paraboloid surface over a spatial neighborhood of yield monitor data around the point to be mapped, so that the influence of outliers is bounded or canceled completely. The neighborhood used looks like the top view of the shape of the wings of a butterfly gliding along the harvest tracks. To determine the optimal size and shape of the neighborhood, an experiment was conducted with yield data measured by a plot combine (called as true values) as well as yield monitor data from a commercial combine with a wider head, which then harvested the same stretch behind the plot combine. The commercial combine was equipped with two monitors. The yield maps are considered to have been optimized if the mean squared deviations (mean squared error) between the true and mapped values has been minimized. A large neighborhood proved necessary for both yield monitors, with the result that the best yield maps obtained appear to be very smooth. Both yield maps could be optimized further by rescaling the yield map values so that their dispersion increases. The yield maps from the Flowcontrol monitor have some lines across the tracks because the optimized butterfly neighborhood is too narrow along the direction of travel. This should be avoided by replacing the butterfly neighborhood by an elliptical one.