Participatory 3-Dimensional Mapping (P3DM) consists of building stand-alone large-scale relief maps made of locally available and cheap materials (e.g. carton, paper, cork) over people overlap thematic layers of geographic information. P3DM enables the mapping of landforms and topographic landmarks, land cover and use, and anthropogenic features, which are depicted by push-pins (points), yarn (lines), and paint (polygons). Participants plot land use and other geographical features and differentiate them according to their vulnerability. Pins of different shapes, sizes and colours enable differentiating building materials and locating the most vulnerable people in the community. Members of the community eventually delineate hazard-prone areas and locate local resources to face these threats. It is then easy and quick to evaluate disaster risk based on hazards, threatened assets, vulnerabilities and capacities. P3DM then enables the planning of disaster risk reduction (DRR) measures based on multi-stakeholder group discussions, helping to find consensus among participants.
Therefore, P3DM fosters the participation and collaboration of a large range of stakeholders, i.e. scientists, government officials, NGOs and local communities, thus enabling the integration of bottom-up and top-down risk reduction measures (Fig. 1). P3DM provides a tangible tool where the most marginalised people, who may have a poor understanding of scientific concepts, can discuss DRR with scientists, who may have a poor understanding of the local context. All stakeholders can contribute their knowledge on the same tool and in the same forum. P3DM is credible to both locals, who build the map and plot most of the information, and to scientists as well as government representatives who can easily overlap their own data and plans on scaled and geo-referenced maps. In the process, NGOs serve as facilitators and moderators.
Despite all its advantages, P3DM is not a stand-alone tool and needs to be combined with other participatory tools, notably to capture the dimensions of vulnerabilities and capacities which are difficult to plot on a map, e.g. interpersonal relationships and temporal patterns. In addition, as for all participatory tools, the contribution and sustainability of a P3DM project depend upon the process of participation and the respect of local needs and aspirations. Having a nice map is not an objective per se: this needs to be of use to foster a dialogue amongst actors of DRR, facilitate disaster risk assessment and eventually to plan for disaster risk reduction.