Remote Sensing and GIS glossary

Acronym for radio detection and ranging. A device or system that detects surface features on the earth by bouncing radio waves off them and measuring the energy reflected back.

A measure of the intensity of backscattered radar energy from a point target. Expressed as the area of a hypothetical surface which scatters radar equally in all directions and which would return the same energy to the antenna.

A measure of the back-scattered energy from a target with a large area. Expressed as the average radar cross section per unit area in decibels (dB). It is the fundamental measure of the radar properties of a surface.

Closeness to which the result of a measurement conforms to the correct value of a physical quantity of interest.

Describes the ability of a sensor to distinguish objects viewed in the same part of the electromagnetic spectrum. It is often represented by the bit depth, or sensitivity, of the sensor. Typical sensors have 8bit, 11bit 12bit or 16bit depth per band; the higher the bit depth the higher the sensitivity and radiometric resolution of the sensor.

Spatial resolution in the range direction, which is determined by the pulse length of the transmitted microwave energy.

Matrix of cells (or pixels) organized into row and columns where each cell contains a value representing information.

Scattering mechanism taking place if the target size is much smaller than the wavelength resulting in resonant effects.

Data that is available immediately after observation.

A measure of the light or heat reflected off a target object.