The GHCC's application of thermal remote sensing to precision farming has its foundation in ecological thermodynamics which states that ecosystems develop to maximize energy throughput and maintain the lowest possible surface temperature. In agriculture systems this translates to greater leaf area and greater rates of water evaporating from leaves, which is directly correlated to yield. The other technology joining the field is precision agriculture, derived from a different aspect of space. Since the mid-1990s, farmers increasingly have used navigation satellites originally designed for the military. By linking sensors that measure yield as crops are harvested with a series of navigational fixes every few feet, and then cranking the data through a computer, a farmer can get an accurate image of how productive different parts of a field are.
Satellite navigation expands the potential value of high-altitude imagery.
But it wouldn't mean anything because you couldn't match it against ground data. 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.