The cities infrastructure is being populated with a large number of Internet-connected devices used for monitoring and management to create a Smart City system. A large part of the city infrastructure has linear form, such as e.g. roads, energy or water distribution networks. In this paper, we present a solution for representation, processing and providing to external IT systems the data related to linear infrastructure. We present the idea of representation of such networks in a form of a multigraph that is stored in graph database and the graph generator which merges the data gathered from monitoring devices with network topology and other representative structures. We propose the architecture of a sample linear infrastructure management system based on multi-graph representation and discuss how it proposes a performance evaluation method based on data generation on the example of a district heating system.