The Open
Geospatial Consortium (OGC) Web Coverage
Server (WCS) specification addresses the access of multi-dimensional data that
represent coverages. The current version of WCS (1.0)
only supports grid and image data types. However, the WCS specification design
and the OGC Coverage Abstract Specification allow for a broader interpretation
of what a coverage entails. The DataFed WCS includes point monitoring data as a coverage. For example, the observations
collected at air quality monitoring stations are coverages
because, taken as a whole, they represent the state (in space and time) of a
spatially continuous phenomena. The actual air quality monitoring stations
themselves are considered features as they represent discrete objects with an
associated set of attributes (station type, start date, operator,…) are accessible through WFS and the emerging SOS
specifications.
A tool to help create DataFed
WCS requests is available: http://webapps.datafed.net/wsquery.aspx
WCS GetCapabilities
DataFed’s response to the WCS GetCapabilities request returns an XML file listing the datasets that can be queried using a GetCoverage request:
http://webapps.datafed.net/ogc.wsfl?SERVICE=WCS&VERSION=1.1.0&REQUEST=GetCapabilities
WCS GetCoverage
The GetCoverage request returns data in the requested format. An example GetCoverage request:
WCS DescribeCoverage
The DescribeCoverage request returns the structure of a coverage. For example, for the IMPROVE monitoring network: