Josephine military map survey (1763-1787) maps are evaluated as a source for the study of past landscapes. The short theoretical introduction stresses the potential of the maps for cognitive studies. In order to use these maps as a hard-data source certain methodological rules must be followed, though. These rules are explained with case studies regarding path-network, hydrological-network and land-use. The most important realisation of this paper is that these maps should be used primarily as a qualitative source; in order to be used as a quantitative source for direct statistical comparison additional analyses must be performed.