Submitted
2025 Global Climate Challenge

Open Community Cadastrals

Team Leader
Pete Masters
Our solution will enable communities in Freetown to create precise cadastral maps of their land occupancy/tenure at a fraction of the market cost using open tools and processes. These cadastral maps, validated by a co-designed community consensus process, will allow residents to access many legal, economic, and social benefits of secure land tenure, have a better chance of establishing formal...
What is the name of your organization?
Humanitarian OpenStreetMap Team (HOT)
What is the name of your solution?
Open Community Cadastrals
Provide a one-line summary or tagline for your solution.
Unlocking climate adaptation investments for informal (slum) communities by solving the challenge of community land tenure
In what city, town, or region is your solution team headquartered?
Washington, DC, USA
In what country is your solution team headquartered?
USA
What type of organization is your solution team?
Nonprofit
Film your elevator pitch.
What specific problem are you solving?
What if the urban communities most vulnerable to climate change effects had more agency to implement climate solutions? The UN estimates that 1.1 billion people live in informal settlements globally. In Freetown, Sierra Leone, more than 360,000 live in slums vulnerable to heatwaves, flooding, and landslides. The potential for people in these settlements to make their homes more climate resilient is significant and it is blocked by social instability that results from a lack of land tenure. A key part of this problem is people’s inability to demonstrate ownership or residency of land and housing through reliable, high-quality and validated geospatial data (cadastral maps). This leaves them vulnerable to losing their homes so they have little incentive to invest in climate-resilient construction or improvements to communal infrastructure, such as green spaces. In parallel, cities are unable to implement the tax revenue systems to finance climate improvements or provide services such as waste management. With urbanization accelerating, this problem is only increasing. Solving the problem of accurate and validated geospatial data gets communities and authorities a big step closer to the benefits of secure land tenure and more climate resilient cities.
What is your solution?
Our solution will enable communities in Freetown to create precise cadastral maps of their land occupancy/tenure at a fraction of the market cost using open tools and processes. These cadastral maps, validated by a co-designed community consensus process, will allow residents to access many legal, economic, and social benefits of secure land tenure, have a better chance of establishing formal residency or ownership, and derisk individual and city investment in construction and retrofitting that is more sustainable and climate resilient. Together, we will conduct high quality surveys and accurate delineations of local plots by building communities’ capacity to fly low-cost drones, use GNSS receivers and undertake field mapping using available smartphones, all supported by free and open source software and data platforms such as OpenStreetMap. This combination of cutting edge open tech, deep local knowledge and effective grassroots-based strategies for collective action and community organising will enable digital representations of informal neighbourhoods, accurate to a few centimetres, as well as leaving a legacy of local capability. In Freetown, where floods, landslides and heat are significant threats, this will increase access to finance for family, business and community investments in better building materials, drainage systems and green spaces.
Who does your solution serve, and in what ways will the solution impact their lives?
Establishing social tenure through Open Community Cadastrals will mean people experiencing the highest rates of multidimensional poverty in Freetown are better able to manage land as an asset, access credit, assert their rights and residency, reduce economic losses, and crucially take autonomous action to make their homes and businesses more climate resilient. This in addition to the hundreds of people that will develop new, marketable digital skills and capabilities. For these communities, climate resilience means; more permanent homes and businesses built with materials that mitigate extreme temperatures, installation of drainage and flood defenses that protect them from extreme weather events and increased access to safe water and sanitation facilities, reducing the burden of disasters and disease outbreaks. Recent research by Slum Dwellers International (SDI) concluded that “to support access to affordable and resilient materials, it is indispensable to address the challenges of tenure insecurity as a foundational first step”. At city scale, Open Community Cadastrals can benefit hundreds of thousands of people in informal settlements in Freetown, supporting climate resilient communities with positive impacts on health and livelihoods in the medium term, as well as longer term prospects of formalization, third party investment and economic benefits for the city.
Solution Team:
Pete Masters
Pete Masters
Special Projects Advisor