Résumé
Although land managers and policy-makers generally have a good experience of what result can be expected from their decisions, they are often faced with difficulty when trying to communicate the visual impact of a future management option to all stakeholders (local and regional decision-makers, land managers, landscape planners, and various communities involved in outdoor activities). Three-dimensional visualisation of the landscape is often used for communicating with the stakeholders. Static, web-based landscape visualisation tools have made considerable progress in recent years, such as for example Google Earth, covering the entire planet in 3D. Such visualisations are based on aerial (satellite) imagery, at a specific date, but are not dynamic. The challenge in methods for integrated assessment of agricultural systems (such as developed in SEAMLESS) is to view future changes in land use, according to scenarios. A 3-D landscape visualisation component has been developed. It is to be launched at the end of a scenario simulation to allow for exploration of landscape changes. Pressures causing such changes will come from a bio-economic farm model; they are then translated into changes in the spatial configuration of the landscape. For each simulation, representing one new agricultural policy, SLE (Seamless Landscape Explorer) processes the input data to build a “virtual scene”, which is saved in a project file. Such files can be used to visualise a scene previously calculated by the land-modeller, for example from a different viewpoint or to produce a film by navigating within the scene. Satellite or aerial imagery or generated textures are draped over the Terrain. The different types of land-use are visualised thanks to a library of detailed textures, and vegetation can be added and visualised according to specific vegetation models. The building process then assembles the 3D landscape model, and displays it in the viewer. Such qualitative outputs can be used in a post-modelling analysis, and/or in the negotiation phases. Such visualisation could have a significant implication for the choice of effective land-use policy, and could be used as a basis for discussion and negotiation within the community. An example of four different scenarios in the French Languedoc-Roussillon region is presented here