Precision Agriculture
Glossary
D
DATA LAYER (in GIS). A layer of information on a GIS map. A map can have many layers to present different types of information. For example, the first layer of a map may be a satellite image of an area. The next layer may have only lines that represent roads or highways. The next layer may contain topographic information and so forth.
DIFFERENTIAL CORRECTION. Correction of a GPS signal that is used to improve its accuracy (to less than 100 m/~330 ft) by using a stationary GPS receiver whose location is known. A second receiver computes the error in the signal by comparing the true distance from the satellites to the GPS-measured distance.
DIFFERENTIAL GLOBAL POSITIONING SYSTEM (DGPS). A method of using GPS that attains the position accuracy needed for precision farming through differential correction.
DIGITAL ELEVATION MODEL (DEM). A digital representation of a surface used for topography.
