Glossary of Terms - P


The repeatability of multiple measurements of the same object or condition.


Refers to the map created in a GIS which assigns product application rates for variable rate applications. Prescription information is exported to a controller for application. Prescription maps are commonly used for variable rate seeding, fertilizer, lime and irrigation.

Prescription File

A computer generated GIS file that assigns a value to a given geographical area. Example: Nitrogen application rate.

Proximal sensing

Using sensors or instruments close to the object being measured, but not necessarily in contact with the object.


An estimate of the true distance (range) from a GPS receiver to a satellite. The estimate contains some error due to atmospheric perturbations and the offset between the receiver’s clock and the satellite clock.