Over the past 5 years, a system for the automated analysis of multi-spectral remote sensing data has been developed by the Centre d'Etudes Techniques de l'Equipement (C.E.T.E.) for use on digital data derived from aerial photographs. This system has been used to date to study the dispersion of effluents in the sea by means of their colour or using a fluorescent tracer, rhodamine B. Accurate photometric techniques are utilized and the originality of the method lies in the way the spatial quantification of the amount of pollutant (or rhodamine) is achieved. Two actual applications are used to illustrate the method. Automated processing is now carried out at the Laboratoire d'Astronomie Spatiale, Marseille (L.A.S.).