This paper addresses the problem of exchangingcomplex data between the constituent systems in a system-ofsystems. This is necessary to ensure that they have compatibleunderstandings of the world surrounding them and entails aneed for semantic interoperability between the constituents.Through a case study of a road construction system-of-systems,the world wide web technologies of linked data and ontologiesare explored as a framework for data representation andexchange. This data includes several broad categories, such asassets, interfaces, organizations, capabilities, missions, andobservations, as well as various properties of those. It is alsodiscussed how the constituents can use this data for reasoningand decision making. The results have been validated through asimulation-based research prototype of the road constructioncase, from which experiences are reported.