Yield mapping based on robust fitting paraboloid cones in butterfly and elliptic neighborhoods

This paper deals with establishing the appropriate size of neighborhoods for fitting paraboloid cones used in both raw yield data correction and yield mapping. The raw yield data correction is based on a neighborhood which looks like a huge butterfly flying along the harvest track, whereas the final yield map is generated using values on an elliptic selection. Both neighborhoods are wider perpendicular to the current direction of travel than they are along its length. In order to find the optimal size of both, an experiment was conducted on the “Lamprechtsfeld” in Germany. Measured yield values from a plot combine (true values) were obtained, as well as yield monitor data from a commercial combine with a wider head which then harvested the same stretch again! Both yields are expressed as a percentage of the average of the corrected yields. The yield map is considered to have been optimized if the sum of squares of deviation between the true plot values and the corresponding yield map values has been minimized. To this end, an unusually large selection region proved necessary, with the result that the best achievable yield map appears to be very smooth.