Abstract: In a parallelepiped agricultural baler flake transfer events are sensed e.g. by the activation of a pre-compression chamber switch or other means indicating that the pre-compression chamber is full and a signal is sent to the baler control logic. The baler logic records in memory the GPS location of the baler at the time of the flake transfer event. A map is then generated showing the GPS location of each flake transfer event. The average crop quantity per flake is determined e.g. by weighing a finished bale and dividing the bale weight by the number of flakes per bale and programming the information into the baler logic. Finally the crop yield for a given field area is determined in the baler logic by multiplying the average crop quantity per flake by the number of flake events recorded in the given area.