The work of the ANR CHOUCAS project has allowed us, among other things, to propose a spatial reasoning model and a geo visualization environment dedicated to the search for victims in mountains, integrated through two interconnected prototypes called RUITOR and GASPAR, respectively. This chapter describes how the uncertainty and imperfection inherent to the process of locating a victim in the mountains have been taken into account in these two elements of the project. It presents the sources of the imperfection that must be taken into account in the application case of victim location in the mountains. Imprecision can be identified at the level of the locational relation, since the notion of “close” can be interpreted differently from one victim to another. The chapter summarizes the results obtained and opens up perspectives for the future.