District Heating Networks (DHNs) are part of the solutions towards a low-carbon energy transition for space heating, making an efficient use of renewable or waste energy sources. In early-stage planning, their potential is often evaluated at the demand side, using large-scale building energy models. However, from the financial and energy efficiency standpoints, the actual potential is also depending on the development of the physical pipework connecting the supply heating station with the consumer substations. To this end, this work proposes a framework for the automated generation of a plausible network layout by solving a minimum spanning tree problem connecting the different stations and assigning a sizing peak power to each network element. Although fully adapted to data available in other contexts, we show here an application using Swiss open geodata, which allows for a quick analysis for any location in Switzerland with a few user inputs. The application in Broc (CH) shows a good match with the operating DHN in terms of piping linear length.