地理信息系统常用词汇及短语及其英文释义

地理信息系统常用词汇及短语及其英文释义

Acceptance test A test for evaluating a newly purchase system's performance and conformity to specifications. Access time A measure of the time interval between the instant that data are called from storage and the instant that delivery is complete

Accuracy Conformance to a recognizable standard;can often mean the number of bits in a computer word available in a given system(see Precision).The statistical meaning of accuracy is the degree with which an estimated mean differs from the true mean.See Precision.

Acoustic coupler A device that enables a computer terminal to be linked to another over the telephone system via the handset of a conventional telephone.

Active System In remote sensing,a system that provides its own source of the electromagnetic radiation to be reflected or scattered by the object being sensed.For example,radar is an active microwave system since the radar system emits energy which is later detected.In contrast to a passive system.

Addressable point A position on a visual display unit(VDU) that can be specified by absolute coordinates.