This chapter focuses on a set of tools that are designed to provide the best information possible, namely a geo-referenced database comprising a spatial analysis framework given by the ecological mapping and computer methods to solve the complex problem of ranking scenarios according to criteria that are weighted differently by each participant. The ecological reference framework is a group of decision aid tools for land-use planning, development and natural resources management. The use of multicriteria analysis is more and more popular when it comes to solving problems that have an environmental dimension. Scenarios are evaluated using the available geo-referenced data, ecological reference framework data, spatial information derived using geographic information system analytical tools, as well as a few conventional tools. The integrated decision aid system associated with a multicriteria approach helps bring together the different regional land planners and managers with groups affected by their decisions.