Through an initiative from LITEAU, an exploratory approach has been implemented and developed (Debaine & Robin, 2012). The general principle is as follows. Effective coastline management in areas where there are sand dunes can be considered on three interconnected levels: a management intervention level in the field, where the problem is addressed directly; an intermediate level of detailed diagnosis, whereby decision-makers develop a targeted response strategy based on their overview of the condition of the dune system; and a more general level, whereby dune systems are listed and classified at an aggregate level to generate spatial statistics about their condition.
To visualise the extent of protection afforded against marine weather hazards, a number of geoindicators for dune formations, plant cover, anthropization and dynamics were identified (see examples of geoindicators in the table on p.72) and spatialised using generic data (LIDAR, aerial photographs, satellite images).
These geoindicators were inserted into specially constructed spatial units (boxes) located at zero metres NGF, with a width of five metres, and extending back a distance of three hundred metres from the coastline. By linking these geoindicators in the boxes, through spatial reasoning, it is possible to make a multi-criteria assessment of the extent of protection offered.