Coverages advertised by a service can be stored on the corresponding server, but the service may well itself rely on external data sources to substantiate the portfolio. In any case, the appearance towards the service clients always is one homogeneously accessible coverage offering. p. 2 For future versions it is intended, to extend WCPS to incorporate further coverage types defined in the OpenGIS Abstract Specification (Topic 6, "The Coverage Type", OGC document 00-106), in synchronization with WCS.