An essential support for environmental monitoring activities is a rigorous definition of an homogeneous
cartographic system required to correctly georeference the acquired data. Furthermore, since the 2007, the European
INSPIRE Directive (INfrastructure for Spatial InfoRmation in the European Community) affirms the necessity to
harmonize the European maps for permitting cross-border analysis. For satisfying these requirements, the authors have
developed a procedure for the cartographic harmonisation in the cross border area studied during in the European
project ALCOTRA (Alpes Latines- COopération TRAnsfrontalière) – ALIRHyS (Alpes Latines- Individuation
Resources Hydriques Souterraines). It concerns the hydrogeological study of various springs and other water resources
in an area between Italy and France including their constitution in a cross-border system. The basic cartographic
information is obtained from existing national maps (Italian and French data), which use different reference systems and
are produced from different data acquisitions and processes. In this paper the authors describe the methods used to
obtain well-harmonised middle-scale maps (aerial orthophotos, Digital Terrain Model and digital maps). The processing
has been performed using GIS software or image analysis software in order to obtain useful and correct cartographic
support for the monitoring data, even if the obtained maps could be further analysed or refined in future works
