Risk management seeks more and more the mobilization of all citizens, including elected representatives and inhabitants. Three-dimensional (3D) geovisualizations have been used between 2009 and 2017 in order to associate citizens to flood mitigation policies along the river Rhône. We focused our studies on the effects 3D geovisualizations can have on the communication and understanding of information and their ability to foster exchanges between heterogeneous actors as well as participation of the grand public to planning processes. Facing both discrepancies in scientific studies of the uses of 3D geovisualizations and a lack of validated theoretical elements, we resorted to an exploratory method based on grounded theory and ethnographic observation in order to produce empirical knowledge on the uses of 3D geovisualizations in collective settings, including heterogeneous actors (risk managers, elected representatives, citizens). Observation showed that 3D geovisualizations can be useful for the dissemination of information about flood risk. Many observed effects were not anticipated during the production of 3D geovisualizations. Qualitative analysis of empirical data through actor–network theory and from a communication studies perspective shed light on some factors influencing the roles of 3D geovisualizations and help put into perspective existing and sometimes contradictory scientific works on 3D geovisualizations’ uses.

Keywords: 3D geo-visualization, Public participation, simulation, stylization, urban regulation 3D geo-visualization is more and more used and appreciated to support public participation, and is generally used to present predesigned planned projects. Nevertheless, other participatory processes may benefit from such technology such as the elaboration of urban planning documents. In this article, we present one of the objectives of the PLU++ project: the design of a 3D geo-visualization system that eases the participation concerning local urban plans. Through a pluridisciplinary approach, it aims at covering the different aspects of such a system: the simulation of built configurations to represent regulation information, the efficient stylization of these objects to make people understand their meanings and the interaction between 3D simulation and stylization. The system aims at being adaptive according to the participation context and to the dynamic of the participation. It will offer the possibility to modify simulation results and the rendering styles of the 3D representations to support participation. The proposed 3D rendering styles will be used in a set of practical experiments in order to test and validate some hypothesis from past researches of the project members about 3D simulation, 3D semiotics and knowledge about uses.

Nous proposons dans cet article un retour réflexif sur une étude des usages de l’information géographique représentée en 3D, dans le contexte de la prévention du risque d’inondation. Ce retour s’appuie sur un projet de recherche-action visant à développer des dispositifs géomatiques innovants à l’appui de la sensibilisation au risque des riverains du Rhône et à comprendre les effets de ces dispositifs sur le grand public. Pour cela, des chercheurs en sciences de l’information et de la communication ont été sollicités pour travailler aux côtés des géographes, géomaticiens, informaticiens et praticiens et pour observer et analyser la production et les usages des dispositifs produits. L’article présente les cadres théoriques utilisés et les résultats de cette évaluation, pour en tirer des perspectives et propositions méthodologiques pour étendre et améliorer l’analyse des usages de l’information géographique et ses représentations numériques 3D dans des contextes multi-acteurs notamment. This paper aims at presenting feedbacks from a reflexive study on how to analyse the uses of geographic information when represented in three dimensions in the field of flood mitigation policy. It draws from a research-action project focused on the development of innovative geographic representations so as to enhance flood risk awareness and on the evaluation of the effects of those visuals on citizens from potentially flooded areas. Scientists in Information and Communication sciences were involved in the project, along with geographers, GIS specialists, computer scientists and practitioners, in order to observe and analyse how those visuals were produced and then used with riverside residents along the river Rhône. This paper presents the concepts and theories that were resorted to to perform these analysis, the results of these evaluations and then draws methodological insights to enhance the study of the various uses of geographic information, especially when represented in three dimensions and used in collective settings, involving heterogeneous actors.