A round baler (100) is disclosed. The baler (100) comprising: a bale chamber (122) having one or more bale forming apparatus (118) which form a bale (B) in the bale chamber (122) a size sensor (134, 146) which measures a plurality of dimensions of the bale (B) as the bale (B) increases in size from a partial bale (B) to a completed bale (B) a force sensor (140) which measures a ending weight of the bale (B) upon completion a location determining device (142) which establishes a plurality of locations of the round baler (100) corresponding to the plurality of dimensions of the bale (B) a controller (180) configured to determine a plurality of yields for the bale (B) by correlating changes in the plurality of dimensions of the bale (B) with the ending weight of the bale (B) and generate a map (150) by correlating the plurality of yields with the plurality of locations. Further, a method of creating a yield map (150) for such a round baler (100) is disclosed.
