INFLUENCE OF THE MARGIN OF ERROR RELATED TO THE USE OF AERIAL PHOTOGRAPHS ON THE INTERPRETATION OF THE SHORELINE CHANGES: EVIDENCE FROM THREE CASE STUDIES FROM THE ATLANTIC COAST OF MOROCCO

In mesotidal environments, the monitoring of shoreline changes is hampered by the uncertainties in the determination of this line on aerial photographs. This paper discusses and evaluates the importance of taking into account the margin of error related to the use of aerial photographs on the interpretation of the shoreline changes. To demonstrate this effect, three cases were selected and studied using aerial photographs from 1946 and 2016 (70-year period). The selected sites on the Moroccan Atantic coast are very close to each other but evolve differently. In this study we calculated the margin of error and we compared it to the rate of shoreline change. Through a statistical analysis we have clearly determined the effect of taking into account the margin of error on the results. In fact, particular attention must be taken when the shoreline of a beach varies slightly.