These problems concern, for instance, the use of land and supporting infrastructure and facilities and their environmental and social impact (González, Kelly, & Rymszewicz, 2020;Nuissl & Heinrichs, 2011). Spatial planning problems vary in complexity, degree of structuration, and geographic scope (Georgiadou & Reckien, 2018). Many of them can be characterised as "wicked" or ill-defined problems as they are usually interconnected with other problems (Lundström, Raisio, Vartiainen, & Lindell, 2016); different people are affected; and, there is uncertainty on the origin of the problem, the possible solutions, values of and acceptance by beneficiaries (Flacke & de Boer, 2017;Goodspeed, 2015; Panagiotopoulou & Stratigea, 2017).Geoinformation (GI) tools can be used to address spatial planning problems in different ways, e.g., as a problem solver, problem mediator or problem recogniser, depending on the problem's wickedness (Georgiadou & Reckien, 2018). In the first case, GI tools are utilised to provide solutions to structured problems with certain causes and effects; in the second case, GI tools can provide a platform to address stakeholder participation and geoinformation analysis in semi-structured problems; in the third case, GI tools can be utilised to explore the uncertain causes and effects of 'wicked' or unstructured problems. In particular, GI based planning support systems (PSS) that offer interactive map visualisation and analytical capabilities aim to contribute in two ways: they may help improve the social interaction during the process, e.g., more inclusive or more interactive, or improve the outcome of the process, e.g., more suitable plans (Newton & Glackin, 2013;te Brömmelstroet, 2013). To do so, PSS utilise maps as means for learning, information exchange, discussion, analysis and decision making (Rambaldi, Kyem, McCall, & Weiner, 2006). We can distinguish three main categories of PSS, namely informing PSS, communicating PSS and analysing PSS (Vonk, 2006). Informing PSS intends to make the planning related information and knowledge accessible and understandable for users; communicating PSS focuses on facilitating communication and discussion among stakeholders, and analysing PSS aims to