Mapping for food safety

How and why communities in Nairobi’s informal settlements are creating and using maps to ensure their food and the people who sell it are safe

Air balloon photograph of children while mapping Mathare informal settlement, Nairobi.

A red balloon more than a metre in diameter rises above tin roofs in Mathare, one of Nairobi’s biggest informal settlements. As the balloon’s handler walks through the narrow alleyways, a camera dangling from the balloon snaps a photo every second. This eye in the sky is helping the community identify and deal with threats to their daily food supplies.

The balloon is just one part of a mapping project led by community members and Muungano wa Wanavijiji, a federation of Kenyan slum-dwellers’ associations with support from partners in the Urban Zoo project. By creating the first maps to show food kiosks, mobile street vendors and hazards such as rubbish dumps and open sewers, the project is helping ensure that both food and the people who sell it are safe.

 Mappers launch an air balloon in Mathare, Nairobi. Photo: Sohel Ahmed, DPU, UCL.

Here we describe how and why Muungano used this approach in Mathare and four more of Nairobi’s informal settlements.1

Why maps matter

Informal settlements play key roles in city economies and are home to millions of people worldwide. In Nairobi, for instance, nearly two-thirds of the population lives one of 175 informal settlements. But governments and their official maps, surveys and censuses tend to ignore such places. 

As a result, residents of informal settlements officially do not exist. Their lack of official documentation deprives them of basic services such as piped water, sewers, sanitation, health care, waste collection and schooling. It means they cannot open a bank account, register to vote and exercise all the rights of full-fledged citizens.

Surveying an aerial map of food safety threats in Mathare, an informal settlement in Nairobi Kenya (photo: Sohel Ahmed).

 Surveying an aerial map of food safety threats in Mathare, an informal settlement in Nairobi Kenya (photo: Sohel Ahmed, DPU, UCL).

Maps can shed light on the undocumented and the challenges they face. They can provide a platform for action and advocacy that addresses these challenges. But maps and mapping processes are political. They describe not only geographic boundaries but also what is within these boundaries. A map’s shape and content will therefore depend on who does the mapping.

Community cartography

Local communities rarely have opportunities to define their needs in processes that influence policy. As a result, development programmes are often ill–suited to local needs as they are based on top-down assumptions and misunderstandings rather than local realities. These issues can however be overcome with “methods of organization, mobilization, teaching and learning that build on what the poor themselves know and understand”.2

Shack/Slum Dwellers International (SDI), a network of organisations of the urban poor in 33 countries, has championed this approach through ‘enumeration’, a process by which organised “urban poor communities count themselves, document the lands they occupy and identify alternative lands for housing when needed”.3

This approach to mapping is a technical as well as a political process. It both creates knowledge and provides a basis from which communities can engage local authorities in policy dialogues.

Through community-led mapping processes, local people can collaborate to define their geographical and social boundaries as well as their needs and challenges. By coming together and deciding how they want to describe their space and what story they want to tell, communities can develop a sense of self-empowerment—a feeling that something can be done to address the problems they face. As Muungano’s experience shows, the ways in which data are collected, analysed and reported are crucial to achieving sustainable results.

 1:34 Muki Haklay, Co-Director of Extreme Citizen Science (ExCiteS) at University College London, explains how community-led mapping differs from other type of mapping

Focus on food

Like other SDI affiliates, Muungano has long used mapping and enumerations to gather knowledge local governments lack. It has used such knowledge to encourage local authorities to join forces with communities and develop solutions to problems the urban poor face. In 2012, Muungano members started thinking of ways to improve residents’ access to safe food and at the same time support food vendors, most of whom live in the settlements they serve.

Street vendor in Mathare. Photo: Paolo Cravero.

 Street vendor in Mathare. Photo: Paolo Cravero, IIED.

Food vendors are vital to Nairobi’s informal settlements, feeding thousands of people every day. Selling food is often the only way the vendors, who are mostly women, can make money. But they are often marginalised, stigmatised and even criminalised as a public health nuisance. To many policymakers they are simply invisible.

Muungano realised that data and mapping could challenge negative perceptions and highlight the crucial role food vending plays in generating income and providing the urban poor with affordable meals. Muungano worked with stakeholders from across the community, using a mix of mapping tools and deliberative meetings to explore problems and potential solutions. The project was community-led. Food vendors, livestock keepers, consumers of street food and others all took part and decided together how the project would unfold and how to use its findings.

 3:30 Street food vendors engaged in the mapping project share their views on the process and its outcomes

It starts with dialogue

Before mapping could begin, conversations first flowed among community members about what to map, where and how. Muungano organised focus group discussions that enabled local stakeholders to answer these questions. To be effective, this phase of the process should be deliberative, open and unrushed. It takes time for stakeholders to reach a consensus about common challenges, priorities and how to proceed. In Muungano’s focus groups, participants identified and discussed what information was already available, what should be investigated and who should be included in future meetings.

Subsequent meetings targeted specific interest groups in order to include and understand the various perspectives at play within the informal settlements. These ‘focus group discussions-plus’ used mental mapping exercises to capture local knowledge. Participants located themselves and their communities on paper and/or digital maps, and showed where services, environmental hazards, street vendors, schools, hospitals and other features are situated.

Some mapping processes go little further than this stage. They conclude by superimposing the different knowledge maps to create a composite and taking it back to the community for verification. Muungano pushed well past this stage to create hybrid maps by combining the indoor mental maps with data gathered on the ground and images captured in the sky.4

Aerial mapping

Aerial photographs integrated with on-the-ground mapping and data from qualitative research can illustrate the relation between residents, the space they inhabit and the activities occurring in it.5

But communities cannot simply turn to free satellite images such as those on Google Maps, which are often obscured by cloud or are simply out of date. Companies producing such images have little interest in providing current images of informal settlements.

 Georeferencing aerial images allows them to be combined with other maps. Here are aerial images from Mathare shown on a Google Map.

Low-cost tools such as balloons, kites and drones can, however, produce up-to-date aerial images of parts of the city official maps do not cover (see the guide to balloon mapping below). Through balloon mapping Muungano showed where food vendors operate, the environmental hazards they face in their daily work and the wider settlement’s layout including unoccupied areas.

Guide to balloon mapping

The Public Laboratory for Open Technology Science sells balloon-mapping kits for around US$100. Alternatively, you can build your own. This illustrated guide [PDF] explains how to construct and control a mapping balloon.

You will need:


BalloonA weather balloon. These are available from specialist shops or online retailers. Prices vary from US$10-400, depending on the type of balloon needed. A UV-resistant balloon is less likely to deflate substantially during the flight.


Helium gasHelium gas to inflate the balloon. The place and legislation relative to purchasing helium vary from country to county. This table can help you work out how much gas you will need to lift your mapping kit.


CameraA basic digital camera. This would ideally be a cheap or second-hand camera as it will hang from the balloon during the flight. The camera must be able to take ‘continuous shots’ if the shutter release is held down, or have a time-lapse function to take shots at set intervals.
You may need a rubber band to hold down the camera’s shutter release during the flight. lets you see how many pictures your SD memory card will hold.


BottleA 1–2 litre empty plastic bottle to mount the camera. Instructions are available on the Public Lab website.


Some strong string or monofilament fishing line with a kite reel or similar device to secure and control the balloon. Make sure you also have a pair of gloves and some duct tape to hand.

Balloon mapping works best if there is little wind. In windy conditions, however, kite mapping may be a better approach.

 3:09 Jack Makau, Administrator for Kenya at Slum Dwellers International, explains the benefits of aerial mapping

 2:30 Professor Muki Haklay, Co-Director of Extreme Citizen Science (ExCiteS), explains some challenges to aerial mapping

Making data count

Once the data collection and physical mapping are complete, the results and aerial photographs are shared and discussed with the community. During this process of analysis the primary concerns of residents emerge and are ranked by importance.

In the Mungaano project, this revealed links between food vending, urban health, food security and environmental hazards. The challenges that emerged include risks of contamination from pests, overflowing sewers, livestock and unsafe water, as well as poor hygiene and food handling practices. The analysis6 enabled community members to identify solutions to advocate for, such as:

  • Training to improve food hygiene
  • Clean-up exercises
  • Designated waste disposal sites
  • Improved water provision, sanitation and lighting
  • Communal storage and refrigeration facilities

 The process of balloon mapping in Mathare carried out by members of Muungano wa Wanavijiji and the UCL’s Development Planning Unit


This final phase of community-led mapping is fundamental as it is also the start of a new process of engagement and negotiation with local government. In this context, organized urban poor communities can support their claims with verifiable data gathered through an inclusive mapping process.

By putting themselves on the map, the food vendors of Nairobi’s informal settlements have shown how they much they matter to local food security and what local government and residents can do to recognise and support them. They have become visible.