[3] PGIS combines a range of geo-spatial information management tools and methods such as sketch maps, participatory 3D modelling (P3DM), aerial photography, satellite imagery, and global positioning system (GPS) data to represent peoples' spatial knowledge in the forms of (virtual or physical) two- or three-dimensional maps used as interactive vehicles for spatial learning, discussion, information exchange, analysis, decision making and advocacy.
[4] Participatory GIS implies making geographic technologies available to disadvantaged groups in society in order to enhance their capacity in generating, managing, analysing and communicating spatial information.
A good PGIS practice is embedded into long-lasting spatial decision-making processes, is flexible, adapts to different socio-cultural and bio-physical environments, depends on multidisciplinary facilitation and skills and builds essentially on visual language.
[6] More importantly, by placing control of access and use of culturally sensitive spatial information in the hands of those who generated them, PGIS practice could protect traditional knowledge and wisdom from external exploitation.
[7] The idea behind PPGIS is empowerment and inclusion of marginalized populations, who have little voice in the public arena, through geographic technology education and participation.
In general, neighborhood empowerment groups can form and gain access to information that is normally very easy for the official government and planning offices to obtain.
In a case study of a group in Milwaukee, residents of an inner city neighborhood became active participants in building a community information system, learning to access public information and create and analyze new databases derived from their own surveys, all with the purpose of making these residents useful actors in city management and in the formation of public policy.
[citation needed] Some of the spatial data that the neighborhood wanted was information on abandoned or boarded-up buildings and homes, vacant lots, and properties that contained garbage, rubbish and debris that contributed to health and safety issues in the area.
Public Participation in decision making processes works not only to identify areas of common values or variability, but also as an illustrative and instructional tool.
Spatial tools such as creation of 3D view sheds offer participants new ways of assessing visual intrusion to make a more informed decision.
This creates greater accountability and facilitates the incorporation of stakeholder values to resolve differences and gain public acceptance for vital development projects.
They determined that stakeholders need to learn likely outcomes that result from stated preferences, which can be supported through enhanced access to information and incentives to increase public participation.
Through a multi-criteria spatial decision support system stakeholders were able to voice concerns and work on a compromise solution to have final outcome accepted by majority when siting wind farms.
This differs from the work of Higgs et al. in that the focus was on allowing users to learn from the collaborative process, both interactively and iteratively about the nature of the problem and their own preferences for desirable characteristics of solution.
[27] Similar work has been done to incorporate public participation in spatial planning for transportation system development,[28] and this method of two-way benefits is even beginning to move towards web-based mapping services to further simplify and extend the process into the community.