From Observation to Representation toward Decision Making process
   Christiane Weber   
                                          Nowadays the environmental issues are compelling gradually the urban form design, the landscape dynamics, the constitution and the sharing of urban knowledge between various actors. The need to assess environmental quality induce handling series of information sets, to address priorities issues, to identify required heterogeneous data able to fit multiple objectives, finally to reinforce the development of interactive applications to ease the population participation.

Several directions of research have emerged these last 10 years in Geography information pointing out the capacities of scientific groups to stimulate and promote new media, new interactive supports, new collaborative actions, to propose new capacities to ease information and dialog sharing, to help decision making process and participation "of and between" actors.

The Earth Observation (EO) domain has considerably changed our regard on the world, from successive acquisition by drawing or photographic campaigns to repetitive captures, the increase of information has provided at various scales spatial references, state of the environment or modeling inputs. On urban areas an essential paradigmatic change has appeared close to the 2000 when the spatial resolution element (pixel) passed from bigger than the urban element (a roof, a tree) to smaller than the same element. This has conducted to integrate more heterogeneous information in the methodological approach depending not only on spectral features, but also form, spatial relationship and semantic rules: from the pixel to the object. By the way, despite this enhancement, in many cases, EO is not really used in urban management or urban design, even if environmental information is required and needed to assess quality of resources, Heat Urban Island or urban biodiversity loss.

Several challenges thus rise now, regarding the environmental issues, the social demand and the decision-making processes. How to integrate and take benefit of large heterogeneous set of data? How to ease interaction between actors in order to converge towards acceptable scenario of development? How to promote participatory behavior to help collection of data?

Each of these questions is linked: to data extraction or collection, data management, data representation regarding alternative scenarios, which might feed decision-making process.