The type of data that could be displayed using a GIS may consist of grid soil sample results, Natural Resources Conservation Service soil maps, aerial photographs, yield maps from harvesters, topographical contours, locations of weed infestations, or a farmer's own experience and knowledge. The technology also lends itself to combining the data in new and different ways that can lead to an interpretation of the situation and a better understanding of the relationship among different agronomic variables. GPS technology is used to accurately determine exact locations. In precision agriculture, GPS technology allows users to know the exact location of soil samples or other agronomic characteristics being collected. For example, soil samples could be collected on a grid every five acres across a field, and GPS would allow users to know the exact position from which each sample was pulled.
Sensors measure the amount of reflectance in a prescribed part of the electromagnetic spectrum.
For agriculture, reflectance information in the visible and infrared portions of the spectrum may be used simply as a backdrop to field maps, or in more sophisticated ways for viewing field acreage, mapping field boundaries, detecting crop stress and disease, and detecting crop yield variations within fields. Precision farming allows today's agricultural producers, advisors and researchers to integrate information technology with field and office activities. Among those agriculturalists, yield monitoring appears to be the most extensive site-specific farming technology. The analysis stage in which the GIS information is evaluated to determine the best course of action. The execution stage in which variable-rate technology is used to apply water, fertilizer or pesticides across the field to maximize production.