Duce, D. A.Sagar, M.Louise M. Lever and Mary McDerby2014-01-312014-01-3120053-905673-56-8https://doi.org/10.2312/LocalChapterEvents/TPCG/TPCGUK05/171-178This paper describes a reference model and a markup language for representing processing and dataflow in distributed collaborative visualization applications. The language, skML, enables processing to be represented at each of the three layers: conceptual, logical and physical defined in the reference model. skML is an XML application. A particular feature of the approach is the use of RDF to associate annotations with skML elements, for example to describe resource constraints. An interactive editor for skML and prototype tools to use skML with IRIS Explorer and OpenDX are described. Extension to other visualization systems such as AVS and VTK is discussed. The paper concludes by comparing skML to other languages and environments for scientific workflow.