Numerous yield monitoring and yield mapping systems have been widely

researched and commercialized for various crops over the last one and a half decades.

Yield mapping during grain harvesting (Schueller and Bae, 1987; Searcy et al., 1989) has

been extensively studied and adopted. Examples of yield mapping for other crops include

cotton (Wilkerson et al., 1994; Roades et al., 2000), potatoes (Campbell et al., 1994),

tomatoes (Pelletier and Upadhyaya, 1999), and silage (Lee et al., 2002). Being able to

evaluate the entire farm graphically, in an encapsulated picture, with respect to yield and

other associated field characteristics would tremendously help farmers to more intimately

know their field and thus help them to make important decisions in an efficient manner.

 2.4 Citrus Yield Mapping

 The preliminary on-tree value of all citrus for the 2000-01 season in Florida was

$760 million. In spite of the widespread economic importance of the citrus industry,

currently the Goat system is the only commercial yield mapping system for citrus. Citrus

yield monitoring systems have been under development for several years. The first yield

monitor for citrus was developed by Whitney et al. (1998 and 1999) and Schueller et al.

(1999). In the Goat yield mapping system, yield is measured by mapping the location of a

tub as it is picked by a truck. Citrus harvest is a busy operation and therefore one of the

prime goals of this system is to develop a yield measurement and mapping system that

would not interfere with any of the current harvesting procedures. One advantage of this

system is that there is no need for any change in the harvesting practice involving many

field workers who are often relatively untrained in managing sophisticated equipment.

 A computer is used to coordinate all the operations of the Goat yield mapping

system. It has a crop harvest tracking system (GeoFocus, LLC, Gainesville, FL) that

records a container location (latitude, longitude, and time) whenever the operator pushes