EM 1110-2-2907
1 October 2003
Glossary
This glossary was compiled from Internet Sites at the USGS, NASA, Goddard Space
Center, Canadian Center for Remote Sensing, and the ASPRS
DISCLAIMER: Any use of trade, product, or firm names is for descriptive purposes only
and does not imply endorsement by the U.S. Government.
A
Absolute temperature
Temperature measured on the Kelvin scale, whose base is absolute
zero, i.e. -273 C (0 C is expressed as 273 K).
Absorptance
A measure of the ability of a material to absorb EM energy at a specific
Absorption band
Wavelength interval within which electromagnetic radiation is absorbed
by the atmosphere or by other substances.
Absorptivity
Capacity of a material to absorb incident radiant energy.
Achromatic vision
The perception by the human eye of changes in brightness, often used
to describe the perception of monochrome or black and white scenes.
Active remote sensing
Remote sensing methods that provide their own source of
electromagnetic radiation to illuminate the terrain. Radar is one
example.
Acuity
A measure of human ability to perceive spatial variations in a scene. It
varies with the spatial frequency, shape, and contrast of the variations,
and depends on whether the scene is colored or monochrome.
Additive primary colors
Blue, green, and red. Filters of these colors transmit the primary color
of the filter and absorb the other two colors.
Adiabatic cooling
Refers to decrease in temperature with increasing altitude.
Advanced very high
Crosstrack multispectral scanner on a NOAA polar-orbiting satellite that
resolution radiometer
acquires five spectral bands of data (0.55 to 12.50 m) with a ground
(AVHRR)
resolution cell of 1.1 by 1.1 km.
Aerial magnetic survey
Survey that records variations in the earth's magnetic field.
Aeromagnetic
Aeromagnetic is descriptive of data pertaining to the Earth's magnetic
field which has been collected from an airborne sensor.
AGL
Above ground level.
Air base
Ground distance between optical centers of successive overlapping
aerial photographs.
Airborne imaging
Along-track multispectral scanner with spectral bandwidth of 0.01 m.
spectrometer (AIS)
Airborne visible and
Experimental airborne along-track multispectral scanner under
infrared imaging
development at JPL to acquire 224 images in the spectral region from
spectrometer (AVIRIS)
0.4 to 2.4 m.
AID--Agency for
The United States Federal agency for international development
International Development
projects.
Albedo (A)
Ratio of the amount of electromagnetic energy reflected by a surface to
the amount of energy incident upon it.
Albers Equal Area
The Albers Equal Area projection is a method of projection on which the
Projection
areas of all regions are shown in the same proportion of their true
areas. The meridians are equally spaced straight lines converging at a
common point, which is normally beyond the pole. The angles between
them are less than the true angles. The parallels are unequally spaced
concentric circular arcs centered on the point of convergence of the
meridians. The meridians are radii of the circular arcs. The poles are
normally circular arcs enclosing the same angle as that enclosed by the
Glossary-1
Previous Page
