Since 2009, a large-scale archaeological field survey – the Ager Segisamonensis Survey Project – has been carried out on the Northern Plateau of the Iberian Peninsula, in the Burgos province (Castilla y León), Spain. The aim of this project is to understand the Iron Age/Roman transition in terms of settlement strategies and landscape exploitation. The field survey has been undertaken in the landscape surrounding an Iron Age settlement and the successive Roman city of Segisamo – modern Sasamón. The goal is not the discovery of new settlements, but the recognition of the so-called ‘dwelling landscape’ and its evolution. In this article, we highlight our field survey methodology based on hand-held Global Positioning System (GPS) instruments and the creation of a recording system of ‘aggregation units'.