In this paper we describe GeOasis, a knowledge-based system for providing tourists with information in a similar way a guide guides a user/traveler while they take a journey: In a given a tourist region, while the tourist drives or takes a walk in the region, GeOasis tells the user information relative to tourist Points o interest (POI) of this region. This requires selecting and arranging the POIs according to several constraints. The most common configuration for GeOasis is to integrate it with a GPS navigator. Thus GeOasi knows’’ the route, the position and the speed of the user. This makes it possible for GeOasis to estimate the time available and the places that make up the route. Time and space estimations are two important constraints to take into account for the planning engine of GeOasis, but additional ones are considered: the relevance of each pre-selected POI, the preferences and history of the user and the estimated timing to read each POI