This article tackles the longstanding issue of intermodality head on. From a geomatics perspective, we model both maritime and road networks connecting port and non-port cities taking into account crucial features such as physical geography, shortest paths, and transport costs. This creates the opportunity to study a hybrid network – both planar and non-planar, and the centrality/accessibility of cities in this bi-layered network. Based on the case of Australia, main results convey new empirical findings on how port and urban hierarchies correlate with single-layered and bi-layered connectivity. We discuss main results in the light of network science, spatial science, and transport studies.