A spatial data infrastructure model from the computational viewpoint

The Commission on Geoinformation Infrastructures and Standards of the International Cartographic Association (ICA) is working on defining models of spatial data infrastructures (SDIs). SDI models from the enterprise and information viewpoints of the Reference Model for Open Distributed Processing (RM-ODP) have already been presented. Our model from the computational viewpoint identifies the main computational objects of an SDI and their interfaces, which are modelled using Unified Modelling Language (UML) component diagrams. Presented here is the first comprehensive SDI model from the computational viewpoint, which enhances the understanding of the computational objects and their interactions in an SDI. This viewpoint complements the previous two and together, the three viewpoints contribute towards a more holistic interpretation of an SDI, which is independent of specific SDI legislation, technology and implementations. For the computational viewpoint, we identified six computational objects, SDI Registry, SDI Data, SDI Processing, SDI Application, SDI Portrayal and SDI Management, and their provided and required interfaces. We describe the interactions of the computational objects in stakeholder activities and the roles they play in the different processes of SDI development and use, which we identified as Initiation, Creation, Management, Manipulation, Access, Processing, Evaluation and Liaison. Two tables summarise the SDI services that are provided by computational objects for stakeholder activities and SDI processes.