Situated Learning stresses the importance of the context in which learning takesplace. It has been therefore frequently associated with informal learning or learning outsidethe classroom. Mobile technologies can play an important role supporting this type oflearning, since it mainly occurs on the field. In this paper we present a learning system and amethodology based on the use of patterns. Students learn about patterns by finding instancesof them on the field, or by recognizing new patterns unknown to them so far. The teacherproposes tasks to the students consisting on finding instances of patterns or discovering newones along a path or inside a pre defined area on a map. This work illustrates the role thatgeo-referenced data collected on the field can play in supporting situated learning activities.