In addition, ground data was difficult to acquire. Getting 10 soil samples from the field into a lab for analysis was a major effort. At the same time that satellite navigation became available to the consumer, advanced, low-cost electronics made it possible to add sensors that would sample field conditions as farm combines moved through the field. Coupling the sensors with GPS, farmers now could take dozens or hundreds of soil measurements while planting, fertilizing, and harvesting, and then return days and weeks later to repeat the measurement in the same location. This is the same system used in the highly successful Urban Heat Island experiments.
Calibration is a key requirement for successful remote sensing.
Another is geometric correction so the data taken by the sensor match correctly with elements on the ground. It makes no sense to predict a good harvest from a rock outcrop. Working with Auburn University and the University of Georgia, and their respective agricultural extension services, six farms were selected in Georgia, Alabama, and Tennessee where precision agriculture systems are employed on several private farms. Especially valuable, Wersinger said, is precision agriculture directed by Dr. Paul Kvien of the National Environmentally Sound Production Agriculture Laboratory at the University of Georgia. Flight lines flown during the 1998 campaign.