The Cartographic Assessment of Ecological Potential (CARPO) allows users to characterize the ecological context of a group of sites at several scales (its perimeter and surrounding area) and on the basis of 4 themes: biodiversity zonings, land use (major types of environment, natural character and degree of permeability of territories), ecological connectivity (biodiversity reservoirs and corridors, non-fragmentation of the sector studied), as well as the richness of the territory in terms of heritage species. It is based on a battery of 8 indicators linked to these themes and a system of evaluation thresholds, used to define 3 levels of ecological potential (average, strong and very strong) for each indicator and at each scale of study. The level of potentiality reflects the importance that an ecological element takes on in a study area, and therefore the degree of contribution and responsibility of a site in maintaining this element favorable to biodiversity. It also translates into an alert level for biodiversity that needs to be taken into account at a site. The ecological diagnosis is materialized by means of a cartographic atlas containing a set of commented maps and figures, as well as evaluation grids and radars for the various indicators. CARPO is a decision-making tool, as it enables users to compare the ecological potential within a site with that of its surroundings, in order to define preservation, management or restoration actions; and to compare the extent of potential between the different sites in the group, with a goal of prioritizing action. This guide presents the methodological framework for applying CARPO to a group of sites.