Accurate measurement with sensors on the combine seems to be enough of a challenge for the big manufacturers.
The best way I’ve heard of to get accurate maps is to weight every trailer going into store and use the total tonnage to calibrate the yield map afterwards.
The only yeild maps I have were made by a Deere system over a decade ago now and had no post processing. I had spot wheat yeilds up to 22 t/ha which was probably where the combine had bulldozed. Because of that the colour bands varied wildly between fields and it was very awkward to visually make much use of the pictures.
I have an old RDS yield monitor in my combine now that doesn’t map. While mapping would be nice when crop planning, while combining I really only care about the spot rate t/hr to help judge forward speed along with the loss monitors. At times I think I would be happier not seeing the t/ha displayed while harvesting.
Keeping the RDS calibrated accurately isn’t easy, so it’s easier to use it as comparative. One of the issues that skews the reading fairly often is any greenary/damp material in the clean grain getting built up around the moisture sensor.