In this paper, we develop a method for spatial decision support that combines economic efficiency – measured by the concept of willingness to pay – with a participatory planning tool, that allows for an active collaboration among the actors involved, in such a way that decision makers can draw on the outcomes in their spatial planning and design process. The method is called RITAM, a Dutch acronym for spatially explicit, participatory and interdisciplinary trade-off method, and combines features of three different approaches to achieve an ‘optimal’ landscape. These three approaches are (i) choice experiment approach; (ii) consumer versus citizen approach; and (iii) participatory approach. As such, RITAM can be seen as a valuation technique that makes explicit use of a participatory approach, in which people managing the landscape – in particular the representatives of the different stakeholder groups that use the landscape for different purposes – are engaged. We applied this new method to a case study in the Frisian Lake District (the Netherlands). The result give an indication of the spatial preferences of the population living in and around the area. Although future works is required, RITAM appears to be a suitable method for landscape planning and design processes, taken into account the preferences of the different organised interest groups in an area.