Building web maps in Zanzibar

Authors: Marena Brinkhurst; Jinal Foflia at Mapbox.
This piece was originally published by Mapbox.

Following the 2018 global FOSS4G (Free Open Source Software for Geo) conference held in Dar es Salaam, Tanzania, a group of 30 developers and geospatial professionals from nine countries across Africa gathered in Zanzibar for a two-day workshop on using Mapbox tools with open imagery.

We worked with the World Bank’s Global Facility for Disaster Reduction and Recovery (GFDRR) to gather builders from two pioneering initiatives: Open Cities Africa, a collaboration with teams from eleven cities across Africa to improve disaster resilience and preparedness using open data; and the Zanzibar Mapping Initiative, which has collected high resolution, cloud-free imagery for the entirety of the two islands of Zanzibar using low-cost drones. Both initiatives are creating open data and open imagery on an impressive scale, and are now exploring how they can use these to serve the needs of their communities.

Images: Zanzibar Mapping Initiative,

Given the hands-on focus and the diversity of skill level in the room, we designed a hybrid between a training and a hackathon, leveraging the rich open data available for Zanzibar (in the ZanSDI and ZanSEA open data portals). The participants formed teams and selected project themes inspired by available datasets. We gave an initial orientation on how to create interactive web maps with Mapbox Studio and Mapbox GL JS, then the teams dove into map design, data preparation, and JavaScript — many of them for the first time.

After two days of coding and collaborating, each team presented a live prototype web map to the group and shared their learnings, challenges, and ideas for that they want to do next. The map projects ranged from tools for comparing imagery; to interacting with crowd-sourced data; to visualizations of school enrollment, urban development, and flood prone areas; to an interactive tour of cultural heritage sites in Zanzibar. The projects showcased a range of interactivity from our GL JS library, including clustering, fly-to effects, and pop-ups. Check them out here:


The energy in the room was thrilling. Even after a week-long conference in Dar es Salaam, we couldn’t get teams away from their computers — even for chai breaks! This experience highlighted what’s spurring geospatial innovation across the continent: Highly skilled and passionate individuals, excited to learn from and with each other, fueled by an intense drive to use and create the best tools in the world for the good of their communities and countries. Web maps, drones, OpenStreetMap, routing and navigation, mobile apps, machine learning — these builders have ideas for how to use everything and are charging ahead. We’re so excited to see what they’ll build next.

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A big thanks to Yves Barthelemy of the Zanzibar Mapping Initiative and Nuala Cowan of Open Cities Africa for collaborating on this workshop, and to this year’s FOSS4G organizers for bringing us together in Tanzania.

Open Cities Africa is financed by the EU-funded ACP-EU Africa Disaster Risk Financing Program, managed by the Global Facility for Disaster Reduction and Recovery.