Aerial photography seldom reveals an archaeological site in its completeness at first glance. When dealing with romano-celtic settlements covering large areas the detection parameters become so complex that they require much prolonged investigation, fragments of evidence being accumulated over many years. The « dossier d'objectif » created at Dijon since 1959 combine low altitude photographs, with vertical stereoscopic ones, all of them taken on many different visual reconnaissance sorties. Their analysis enables one to draw plans of two different types of settlements : the large romano-celtic villa, set in its rural environment (roads, soil, lay out of the land...) ; the romano-celtic built-up area, referred to as « secondary ». The study of such areas in Côte-d'Or has brought out their diversity (roaciside of cross-roads, vicus like Beneuvre, harbour emporium such as Lux, oppidum style built-up area like Alésia and Vertault, extensive plain built up area such as Mâlain).