This article proposes a methodology to interpret old aerial photography applied to the geohistorical study of torrential landscapes. Indeed, as a primary source, images are historical proxies which foremost advantages are to locate and spatialise forms of changes. The aim of these researches is to produce a cartographical following of landscapes dynamics, through this type of archive. To achieve such a purpose, we choose a landscape sensitive to changes (torrential fan), considering landscape entities which equilibrium conditions responds to the socio-environmental context of a torrential northern alpine valley. In this exploratory aim of diachronic reconstruction, the photo-interpretative technics and remote sensing were associated. In this article, we explain the potentialities of an object-oriented approach using as an example a time series of areal missions taken by the National Geographic Institute of France (IGN-F©). The results of this method give a spatial and normalised comprehension over the fifty last years.