Mapping informal settlements with AI – expanding access to housing, land and basic urban services | United Nations Innovation Technology Accelerator for Cities (UNITAC) Hamburg

Photo: Informal settlements in the Cape Town area, credit: Filiz Elaerts on Unsplash

Meeting the urgent need for adequate housing and better land use in a world of rapid urban growth

Today, the world is confronted with a global housing crisis. Around 2.8 billion people worldwide lack adequate housing with more than 1.1 billion people living in informal settlements representing one third of the world’s urban population. 230 million of theslum dwellers live in Sub-Saharan Africa.Thesenumbers are rising against the backdrop of rapid urban growth: Growth prediction until 2050 projects that another two billion people will live in slums (183.000 people each day), and that Africa’s urban population will triple in the next 50 years. While urbanization is a major global challenge, it presents a significant opportunity for achieving sustainable development. Through its new strategic plan 2026-2029, UN-Habitat aims to transform informal settlements and slums, and provide adequate housing, land, and basic services for all with the presumption that this transformation will lead to more prosperity and a positive transformation of people’s lives.

Despite investments aimed at upgrading and transforming informal settlements, access to adequate housing, land, and basic urban services including safe drinking water, electricity, sanitation, and reliable public transport remains insufficient for many communities. In South Africa, for example, funds for urban development are allocated based on census data, which is only updated every ten years. This leaves a significant gap in reliable, up-to-date population data—particularly in fast-changing informal neighborhoods. Without accurate data, cities struggle to plan infrastructure development and upgrade settlements effectively.

In the case of eThekwini, South Africa, the Informal Settlement Upgrading Strategy defines informal settlements as areas typically lacking formal, approved town planning layouts and related regulatory approvals, with housing often in the form of “make-shift shacks”. In 2022, the city of eThekwini reported a total of 312,741 households in informal areas, making nearly one quarter of the population. Despite all efforts, mapping and monitoring the expansion of informal settlements was, until recently, a time-consuming and resource-intensive process. Municipal staff relied on manual digitization of aerial imagery, marking structures by hand on images, and conducting on-the-ground surveys. This approach limited the city’s capacity to respond to the fast-changing dynamics of the settlements. As a result, many inhabitants and dwellings remained unrecorded, leaving large parts of the population “invisible” for planning and service provision.

AI-powered mapping for inclusive urban development

As part of an Open Call for Projects, funded by the German Ministry of Foreign Affairs, the United Nations Innovation Technology Accelerator for Cities (UNITAC) partnered with the eThekwini Municipality to strengthen land monitoring and data management. The city identified the urgent need for faster and more accurate mapping of informal settlements, ensuring that infrastructure and service delivery planning can better meet the demands of these underserved communities.

In response to the city’s need and in close collaboration with its teams, UNITAC developed theBuilding and Establishment Automated Mapper (BEAM). BEAM is an AI-based tool that uses machine learning to automatically detect building footprints and structures from aerial imagery. The data generated with BEAM helped the city of eThekwini to identify growth patterns and better understand the dynamics of its informal settlements. This enables the municipality to prioritize upgrading initiatives and ensure that investments reach the communities that need them most.

The BEAM tool dramatically accelerates the mapping process. What once took several months across the entire city of eThekwini can now be achieved in 72 hours. According to the 2022 Census, the eThekwini municipal area contains 1,122,738 households. BEAM mapped 1,530,546 building footprints across the municipality, covering both residential and non-residential structures. These figures are not directly comparable—Census data accounts only for households, whereas BEAM captures all building types. Nonetheless, up-to-date information on informal settlements is essential: it enables the municipality to plan targeted policy interventions, accurately report on performance, and most importantly secure adequate national funding for the provision of free basic services to disadvantaged communities. UNITAC Hamburg is currently working on expanding the tool’s functionalities, including the ability to distinguish between formal and informal structures.

Recognizing the importance of early engagement, UNITAC-Hamburg convened an advisory meeting with relevant stakeholders at the project’s inception to bring in diverse perspectives on the project and its implementation. The session brought together representatives of informal settlements dwellers and other community members, government representatives, NGOs and human rights groups, academia, and institutions working on transparency and data with a people-centered approach. The dialogue served as an important platform to integrating diverse voices and reflections, ensuring that its outcomes would generate a positive impact for communities and vulnerable populations. It also provided an opportunity to assess potential risks and challenges, while exploring synergies and opportunities for continued collaboration, such as the joint participation and presentation of the project in global events including the 12^th Session of the World Urban Forum in Cairo, Egypt, the Hamburg, Germany, Sustainabilty Conference in June 2025 and the World Cities Day in Bogota, Colombia.

In Cape Town, UNITAC collaborated with the city, applying BEAM to high resolution aerial imagery to map informal dwellings. The initiative focused particularly on informal dwellings in the backyards of formal residences - a phenomenon called “backyarding”, a growing housing trend in South Africa. Earlier this year, UNITAC handed over the data to the municipality. As a result, 822,390 additional building footprints were detected with BEAM and integrated into the city’s geographic database. Ground truthing activities conducted by the city showed that the majority of the additional structures were informal dwellings, with only a small number of footprints of formal structures. This helpedthe city to close the data gaps on informal structures missed by the previous deep-learning model, strengthening evidence-based planning and ensuring that resource allocation to upgrading interventions can get aligned with the updated population records.

Beyond South Africa, BEAM has been deployed in Central America as part of UN-Habitat Mexico’s initiative to develop a regional inventory of informal settlements in Central American capitals. Trained on high-resolution satellite images provided by the United Nations Satellite Centre (UNOSAT), the tool was used in eight cities: Belize City, Guatemala City, San Salvador, Tegucigalpa, Managua, San José, Panama City, Santo Domingo. In this process, BEAM generated shapefiles with building footprints providing a spatial overview of settlement location sizes, extents, and key morphological characteristics. Across the eight cities the tool mapped 6324 informal areas and detected 550,776 buildings.

As it happens with many digital tools, factors such as limited access to high-resolution imagery, the need for locally labeled data, and requirements for advanced computing infrastructure and GIS expertise can limit the tool’s deployment and scalability, particularly in resource-constrained settings. At the same time, deploying BEAM in different contexts showed the importance of reliable data access, capacity building and strong local collaboration to ensure accuracy, contextual relevance, and ownership of the results.

Overall, BEAM strengthens cities’ capacity to deliver services where they are needed the most, contributing to the Sustainable Development Goals (SDGs), particularly SDG 11 – making cities and human settlements inclusive, safe, resilient and sustainable. By accelerating the mapping process and providing evidence-based data, BEAM empowers municipalities to plan more effectively, ensure more equitable allocation of resources, and expand access to adequate housing, land and basic services.