Cities are not only extrusions from a homogeneous ground plane, but a volumetric engagement with a physical mass. Historically, the materiality of the city (geology and built form) has been addressed by specific disciplinary or institutional divisions in response to well-defined needs or desired project outcomes. This approach has resulted in conflicts between resources (pollution of aquifers) and lost opportunities for potential synergies (geothermal energy structures or local irrigation). Recent efforts by practitioners and researchers attempt to provide useful spatial information to urban planners about the underground resource potential of their cities, but their mapping methods and outcomes tend to be oriented towards the potential for underground space, ignoring geomaterial, groundwater and geothermal potentials. Furthermore, they address the existing urban form as indicative of demand rather than as a ‘mass’ with its own ‘supply’. The research presented here develops a cartographic method to evaluate underground potential at the level of the capacity of the geology and urban form in three cities on three different continents. It explores, using spatial analytics and econometrics, the Montreal downtown and its Indoor City as a contingent expression of spatial volumetric potential. The resource potential maps produced seek to visualize the distribution of multi-resource underground potential as compasses—as tools for locating the planning process in the urban volume, without prescribing directions to take.   

Michael Robert Doyle holds a PhD from the Laboratory of Environmental and Urban Economics (LEURE) at the Swiss Federal Institute of Technology in Lausanne (EPFL) since 2016. His research addresses the urban volumetrically as a mass of buildings and underground resources, combining spatial analysis with cartography and new materialist philosophy with urban theory.