In 1997, I embarked on a PhD to study mobility among nomadic pastoralists in Senegal. Previous studies had largely been conducted by anthropologists who through ethnographic fieldwork followed the nomadic pastoralists for long periods of time and did their own sketches of the movements. As a human geographer familiar with satellite remote sensing and geographic information system, I pondered how these relatively new technologies could be combined with classic ethnographic fieldwork, which we also use in human geography. I decided to use handheld Global Positioning System (GPS) devices for tracking the pastoralists and their herds. My study was, as far as I know, the first one to use GPS for studying pastoral mobility. A total of 10 pastoralists were trained in using a GPS device and asked to map their movements. This information was combined with satellite imagery, on one hand, and qualitative interviews, on the other. This case study provides an account of the practical aspects of using GPS, taking the reader to the heart of some methodological issues that arose in the course of the research. The case sheds light on the particular challenges in using GPS for eliciting information about pastoral mobility. Thinking about such challenges leads to more general considerations about how to understand mobility not only of nomadic pastoralists. Particular attention is paid to the use of GPS–based maps as a prop for assisting qualitative interviewing, as a fruitful way of drawing out deeper understandings of the use of mobility and what mobility entails from the interviewee’s point of view.