Remote Sensing and GIS glossary

The ratio or relationship between a distance or area on a map and the corresponding distance or area on the ground, commonly expressed as a fraction or ratio. A map scale of 1/100,000 or 1:100,000 means that one unit of measure on the map equals 100,000 of the same unit on the earth.

Multiple reflections of electromagnetic waves by particles or surfaces.

Radar system that emits microwave signals to measure the power received from surface backscattering to infer earth's surface properties by measuring a multiplet of backscattering cross sections. The multiplet of signals typically includes different azimuth views and/or microwave polarizations at wavelengths on the cm scale. Satellite microwave scatterometers are mainly launched to obtain ocean vector winds, but other geophysical variables, such as soil moisture, sea ice and snow parameters, or vegetation are also obtained.

An electronic device for detecting electromagnetic energy and converting it into a signal that can be recorded as numbers and displayed as an image.

The ratio of the level of the signal carrying real information to that carrying spurious information as a result of defects in the system.

The incline, or steepness, of a surface, measured in degrees from horizontal (0–90), or percent slope (the rise divided by the run, multiplied by 100). The slope of a TIN face is the steepest downhill slope of a plane defined by the face; the slope for a cell in a raster is the steepest slope of a plane defined by the cell and its eight surrounding neighbors.

The dimensions of the area on the ground represented by a single cell in a raster. The spatial resolution (e.g. cell size) affects the level of detail represented in an image.

Random constructive and destructive interference from the multiple scattering returns.

The range of wavelengths that an imaging system can detect, including both the number of bands and the wavelength range detected by each band.