Web Coverage Service
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A WCS provides access to coverage data in forms that are useful for client-side rendering, binary xml encoding implementation specification ogc portal input into scientific models, and for other clients. As with WMS and WFS service instances, a WCS allows clients to choose portions of binary xml encoding implementation specification ogc portal server's information holdings based on spatial constraints and other query criteria.
Unlike OGC Web Map Service WMSwhich portrays spatial data to return static maps rendered as pictures by the serverthe Web Coverage Service provides available data together with their detailed descriptions; defines a rich syntax for requests against these data; and returns data with its original semantics instead of pictures which may be interpreted, extrapolated, etc.
As such, WCS focuses on coverages as a specialized class of features and, correspondingly, defines streamlined functionality. The WCS suite is organized as a Core, which every WCS implementation must support, and a set of extensions defining additional functionality. Implementers can choose which extension to support, but there are some basic rules to be obeyed - for example, every WCS implementation must support at least one communication protocol and at least one data encoding format.
To ease overview, extensions have been grouped along five categories: Some of these specifications are briefly presented below. The WCS Core establishes basic spatial and temporal extraction. There are two types of subsetting, which can be combined: Trimming extracts a sub-area of a coverage indicated by a bounding box ; the result has the same dimension i. Slicing performs a cut binary xml encoding implementation specification ogc portal the position indicated, thereby reducing the dimension of the result coverage.
Range subsetting not to be mixed up with the domain subsetting of the WCS Core allows to extract components from structured cells "pixels", "voxels" of a coverage.
Cells are structured if they contain several components, such as the three components red, green, and blue in color images.
For example, from a 7-band Landsat satellite image a range subsetting request may extract the near-infrared, red, and green range components "bands", "channels". The geospatial extent is unchanged, that is: WCS-T T standing for transactional establishes how to binary xml encoding implementation specification ogc portal complete coverages to a server or modify existing coverages on a server.