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abbe prism	A prism system consisting of two double right-angle prisms and reflecting an incoming ray four times to give an erect, inverted image
ABLATION	Removal of a part by melting or vaporization.
acoustic data	À½ÆÄÀÚ·á
ACRIDIDS	A family of orthopterous insects including the grasshopper. All the species of this family can leap. ADAPS--AVHRR Data Acquisition and Processing System The EROS Data Center ADAPS, which began operation in May 1987, receives approximately 6 passes per day of HRPT data over the conterminous United States.
administrative procedures	ÇàÁ¤ÀýÂ÷
AEROMAGNETIC	Aeromagnetic is descriptive of data pertaining to the Earth's magnetic field which has been collected from an airborne sensor.
aeronautical chart	°øµµ
aggregation	Áý´ÜÈ­
AGRHYMET	AGRicultural, HYdrological and METeorological program A West African AGRHYMET program which collects and disseminates environmental information on West Africa.
AID	Agency for International Development The United States Federal agency for international development projects. ambiguity
ALBEDO	The percentage of incoming radiation that is reflected by a natural surface such as the ground, ice, snow, water, clouds, or particulates in the atmosphere.
ALBERS EQUAL AREA PROJECTION	The Albers Equal Area projection is a method of projection on which the 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 other parallels of latitude for a given range of longitude. Albers Equal Area is frequently used in the ellipsoidal form for maps of the United States in the National Atlas of the United States, for thematic maps, and for world atlases. It is also used and recommended for equal-area maps of regions that are predominantly east-west in extent.
ambiguity	¸ðÈ£¼º
ANSI	American National Standards Institute An ANSI standard implies a consensus of those substantially concerned with the scope and provisions of a product and is intended as a guide to aid the manufacturer, consumer, and the general public.
ANTHROPOGENIC	Relating to the scientific study of the origin of human beings and the results of their influence on nature.
APFO	Aerial Photography Field Office The U.S. Department of Agriculture's APFO is managed by the Farm Service Agency (FSA). FSA was formerly known as the Agricultural Stabilization and Conservation Service (ASCS). APFO is the repository for all of the USDA's aerial photography. The archive contains over 50,000 rolls of film acquired over the last 40 years and includes over 14 million frames of coverage of the conterminous U.S., Alaska, and Hawaii. APFO provides photographic products to local county, State and Federal offices within the U.S. Department of Agriculture (USDA) including FSA, National Resources Conservation Service (NRCS), and the Forest Service. They also serve the general public with similar products upon request at the cost of reproduction.
ARC EXPORT	EXPORT creates an ARC/INFO interchange file to transfer coverages, INFO data files, text files, and other ARC/INFO files between various computer systems. An interchange file contains all coverage information and appropriate INFO file information in a fixed length, ASCII format. It can be fully or partially compressed as well as uncompressed ASCII depending upon the given EXPORT option.
ARC SECOND	1/3600th of a degree (1 second) of latitude or longitude.
ARC/INFO	ARC/INFO is a geographic information system (GIS) used to automate, manipulate, analyze, and display geographic data in digital form. ARC/INFO is a proprietary system developed and distributed by the Environmental Systems Research Institute, Inc., in Redlands, California. DISCLAIMER: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. ArcUSA Designed by ESRI, ArcUSA is a general-purpose database used to generate thematic maps of the conterminous United States at the State and county levels. The database contains cartographic information, tabular information, and indices and is designed for a wide range of applications.
area fill	¸éä¿ò
AREAL	Relating to or involving an area.
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ASCENDING NODE	Direction satellite is traveling relative to the Equator. An ascending node would imply a northbound Equatorial crossing.
ASCII	American Standard Code for Information Interchange A seven-bit code standard adopted to facilitate data interchange between computers and operating systems. These codes represent alphanumerics and special characters (for example, $, /, ?, !).
association	°áÇÕ
ASTRODYNAMICS	The dynamics of celestial bodies including the motion and gravitation of natural and artificial objects in space.
ASTRONOMIC	Pertaining to the science of astronomy. Astronomy is the science of the heavenly bodies (fixed stars, planets, satellites, and comets) their nature, distribution, magnitudes, motions, distances, periods of revolution, eclipses, etc.
ATKIS	µ¶ÀÏÀÇ MEGRIN
ATOMIC	ABSORPTION SPECTROPHOTOMETRY This destructive analytical technique is used to determine concentrations of specific chemical elements based on their emission or absorption of specific wavelengths of electromagnetic radiation.
attributes	¼Ó¼º Attributes, also called feature codes or classification attributes, are used to describe map information represented by a node, line, or area. For example, an attribute code for an area might identify it to be a lake or swamp; an attribute code for a line might identify a road, railroad, stream, or shoreline.
attribute accuracy	¼Ó¼ºÁ¤È®µµ
attributes value	¼Ó¼º°ª
AVHRR	Advanced Very High Resolution Radiometer The AVHRR is a broad-band, 4 or 5 channel scanner (depending on the model), sensing in the visible, near-infrared, and thermal infrared portions of the electromagnetic spectrum. This sensor is carried on NOAA's Polar Orbiting Environmental Satellites (POES), beginning with TIROS-N in 1978.
AZIMUTH	Azimuth is the angle of horizontal deviation, measured clockwise, of a bearing from a standard direction.