Participatory 3D modelling (P3DM) is a community-based tool – better defined as a ‘process’ – that integrates local spatial knowledge with data on land elevation and sea depth to produce a physical model. Local communities participate in the model building of the territory that they rely on for their livelihoods and cultural practices. The kind of data that the P3DM process generates are extremely diverse, but essentially it are data that are relevant for local knowledge holders: from land cover and land use to infrastructure – all of which are intimately related to a given people’s culture, their sacred sites, and burial grounds.
Local knowledge holders may be interested in sharing data, but there may also be data that they may consider private and sensitive. However, they may like to locate and document this data solely for their internal use. They may wish to maintain strategic control over the information that is shared, how it is released and to whom.
P3DM has already been used in a variety of contexts: claim land ownership, transfer knowledge across generations, and manage conflicts. It has recently started to take off in the Pacific region, enabling people in small island countries – where rising sea levels are posing a serious risk to many people’s livelihoods – to take informed decisions about how best to manage risk and adapt to climate change.
Origins of P3DMP3DM was initially used in the late 1980s in Thailand, to demonstrate where the Royal Forestry Department was developing plantations for catchment rehabilitation. As such it was a conservation-based demonstration tool, not a participatory tool. Dr Uraivan Tan-Kim-Yong, an anthropologist at Chiang Mai University, was running a research programme involving hill tribe people. She invited her students to make small Styrofoam models and bring them to the villages to discuss soil conservation and soil erosion issues.
These models proved useful and eventually drew the attention of other parties, who began to develop and deploy the P3DM process. The Thai-German Highland Development Programme (TG-HDP) (1981-1998) funded by the German Agency for Technical Cooperation was on the forefront in making use of the tool . For the first time the 3D models began to be used on a village-to-village basis and in a participatory manner. 3D models started to shift from being a demonstration tool to an education tool, and finally a planning tool. In 1993, a workshop was held in Thailand attended by several NGOs from Southeast Asia. Organisations such as the Philippine Association for Intercultural Development (PAFID) and Green Forum Western Visayas began to embrace P3DM and started using it with indigenous people. It enabled them to address the demand coming from tribal minority groups to generate a great deal of data to prove their ancestral occupancy of land and waters in order to get their customary rights of tenure and use recognised by the government. Over the years, P3DM has benefited from the creativity of the many practitioners who have been engaged in the process.
Initial challengesAll new technologies face implementation challenges. With P3DM, the initial one is posed by the availability of sufficiently detailed, up-to-date and accurate digital elevation models (DEMs). For example, some DEMs were produced decades ago. So if a blank model is constructed based on an obsolete elevation model, knowledge holders may point out landscape features that have changed, such as an eroded coastline, a mutated river’s course or slope that was altered by a landslide. Once the DEM issue is solved, the model is populated by local knowledge holders, where they share and visualise their spatial knowledge. People have a lot of fun doing this kind of exercise and get a great deal of gratification from it.
Another challenge is the difficulty of applying P3DM to map out large areas, such as an entire country. P3DM requires substantial preparation and logistics. As a result, the tool is often deployed in hotspots, or critical areas. In small island countries it is a useful tool used to map land and seascapes, and eventually large parts of an entire country.
In certain countries the use of P3DM has had a definite impact on policy. In the Philippines, the government has adopted the process in many different contexts, from conflict resolution to awarding indigenous tenure on land and water. In 2001 the minister of the environment and natural resources signed a memorandum circular that recommends the use of P3DM in “protected area planning and sustainable natural resource management” . As of November 2014, in the Philippines 165 models were made that provided critical data for policy making. Samoa is a more recent case where the government has embraced the process in the context of climate change adaptation and community-based risk management.
At international levels, P3DM has been cited as a recommended process by CTA, UNDP, IFAD, GEF, UNESCO and more recently by IUCN in the context of the 2014 “Promise of Sydney”.
From physical to digitalCustodianship of the 3D model is important to determine where the models are stored and who is responsible for their conservation, use and updating. A model is useless if it is locked up in a room where people cannot access it, or if it is stored under a glass cover and becomes a museum piece. The models have to be part of everyday life. They are used to educate children about local geography and history. This is true of physical models which are usually under the direct control of the knowledge holders. However, their digital representation follows a different path and has usually different custodians.
Once the data goes from physical to digital there is a risk that it will be misused or unwittingly shared. It is crucial that the intermediaries appointed as custodians of the data, are a trusted and reliable entity that will protect the data and respond to the community’s wishes in terms of data sharing. Trust and ethics play an important role in this. Research work may be extractive and could fail to consider that the mapping process should first and foremost benefit the knowledge holders. Unscrupulous individuals may entice people to share data to exploit resources. P3DM implies that a high level of ethics is applied and trust established between the actors involved: the knowledge holders and the technology intermediaries / facilitators.
In 2006 the community of practitioners focusing on Participatory GIS practice has developed a guideline  on practical ethics for PGIS practitioners, facilitators, technology intermediaries and researchers to stimulate the adoption of good practice. It has been published in 12 languages and governs the way people doing participatory mapping should behave in the process of generating, handling, storing and sharing data. The code recommends that knowledge holders remain in full control throughout the process and that data are gathered and eventually shared with their free prior informed consent (FPIC).
For the most part, P3DM data have been well protected. But there have been cases where data entered into a model were misused. In South-East Asia, there are accounts that graveyards located on a 3D model were plundered because such data were not removed and left accessible to the public. Therefore, it is important to make people aware of the implications of geo-locating sensitive data and making it public. They can then decide what to visualise, what to leave or remove from the model.
One of the most important components of a P3DM process is to involve external agencies from the very beginning. This can raise awareness among “outsiders” about the depth, accuracy and relevance of local knowledge. This may induce a new sense of esteem for local knowledge holders.
References P3DM for Participatory Land Use Planning (PLUP) in Thailand, Integrated Approaches to Participatory Development (IAPAD).
 Participatory 3-Dimensional Modelling as a Strategy in Protected Area Planning and Sustainable Natural Resources Management. Memorandum, Department of Environment and Natural Resources, Republic of the Philippines, Integrated Approaches to Participatory Development (IAPAD).
 Rambaldi,G., Chambers, R., MCcall M. And Fox, J. (2006) Practical ethics for PGIS practitioners, facilitators, technology intermediaries and researchers, Participatory Learning and Action, 54, IIED (April) 106-113.
- IAPAD.ORG: Main website for Participatory 3D Modelling (P3DM)
- Largest online library on participatory mapping practice (gray literature)
- Participatory 3-Dimensional Modelling: Guiding Principles and Applications; 2010 edition
- Google Map showing the locations where P3DM has been implemented – non exhaustive list
- PGIS video collection in English
- PGIS video collection in French
- LinkedIn group of professionals interested in PGIS /PPGIS
- Training Kit on participatory mapping practice
- www.ppgis.net Gateway to get in touch with the wider PGIS community. Here you may register on the PGIS discussion list. That's the best channel for being updated on PGIS-related matters and where to post questions and share opinions. The global (English) list has ~3000 members. There are also independent chapters exchanging in French, Spanish and Portuguese.