WCS is the such an important service specification as WFS and WMS, which is familiar to us. Please read and understand the following sections:
The Web Coverage Service(WCS) supports electronic retrieval of geospatial data as "Coverages"-- that is, digital geospatial information representation space -varying phenomena(Note:the spatial-temporal phenomena)WCS支持把地理空间数据当作“Coverage”的数字化信息提取,即:空间变化现象的数字化地理空间信息表达。
A WCS provides access to potentially detailed and rich sets of geospatial information, in forms that are useful for client-side rendering, multi-valued coverages, and input into scientific models and other clients. TheWCS may be compared to the OGC Web Map Service(WMS) and the Web Feature Service(WFS); like them it allows clients to choose portions of a server's information holdings based on spatial constraints and other criteria.
Unlike the WMS, which portrays spatial data to return static maps (rendered as pictures by the server), the WCS provides available data together with their detailed description(在提供数据的同时,提供数据的详细描述); defines a rich syntax for requests against these data(定义了丰富的查询数据的句法); and returns data with its original semantics (instead of pictures) which may be interpreted, extrapolated, etc. - and not just portrayed.(可返回带有原始语义的数据,可以重新解释、推算,而不是仅仅进行描述)
Unlike WFS, which returns discrete geospatial features, the WCS returns coverages representing space-varying phenomena that relate a spatio-temporal domain to a (possibly multidimensional) range of properties.(WCS返回表达和可能是多维的时空领域相关空间变化的现象关联到几个属性的一个范畴)