As Nigeria’s 10th National Assembly gets inaugurated today, the Stears team has been reflecting on our recent quest to map their geographic domains. Where exactly does one House of Representatives constituency stop and another begin?

We were confronted with that question last year when we started scoping Stears Elections, our state-of-the-art, interactive election data platform. We quickly identified a critical data gap that threatened our plans for the 2023 Nigeria General Elections.

Our goal was to provide maps of the House of Assembly and State Houses of Assembly results, but there wasn’t any geospatial data (i.e. sets of latitude-longitude coordinates) for mapping the constituency boundaries. We scoured official and open data sources, but the boundary data wasn’t available.

(Spoiler: We created the data. Data download is available at the bottom of the article.)

Why does this matter?

The mapped boundaries of the Assembly constituencies are critical for several reasons:

1. They enable citizens to reliably determine which constituency they are part of based on their address. This is essential for understanding which candidates will be on their ballot, so they can research them and make informed decisions.

2. They enable political aspirants to understand exactly which neighbourhoods and streets are part of their constituencies. Due to the lack of clear maps, politicians don’t always know where to do outreach or which areas and populations they are responsible for serving.

3. They enable the public to assess political outcomes across dimensions that vary geographically, like demographics and population density. Maps also make it easier to understand how political boundaries intersect with important natural resources and infrastructure.

We recognized the importance of this missing data and embarked on a 6-month journey to create the map boundaries ourselves. It was not an easy task.

How did we do it?

Ward and Local Government Area (LGA) boundaries were our building blocks for creating the shapes of the constituency boundaries. That’s because they are the smallest administrative areas with well-established boundaries provided by GRID3 Nigeria, Nigeria’s open data platform for spatial data. There are 774 LGAs and over 8,809 Wards in the country.

The biggest challenge was finding out where constituencies in the LGAs and Wards belonged. Sometimes half of an LGA would be in one House of Reps constituency, while the other half of the LGA would be in the neighbouring constituency. It wasn’t always a simple one-to-one match. That’s why we needed to use Wards, the smaller building blocks of LGAs.
 

Ultimately, we confidently mapped 99% of the House of Representatives boundaries and 89% of the State Houses of Assembly boundaries. The following maps show the boundaries we created and the handful of gaps where we needed to approximate the boundaries.

For the House of Representatives, we needed to approximate the boundary between Port Harcourt 1 and Port Harcourt 2 in Rivers State because we could not obtain adequate identifying information about the Wards in each constituency.

The information for the State Houses of Assembly was more incomplete and had more inconsistencies between information sources (INEC vs GRID3). Because of this, we needed to approximate boundaries for 106 of the 994 constituencies.

Using the data responsibly

For Stears Elections, our primary goal was data visualisation. We wanted people to be able to visualise how political party preferences varied by region across the country. Because of that, we felt comfortable displaying some approximated boundaries because our primary objective was to demonstrate high-level patterns and trends rather than street-level accuracy.

In the datasets, we have clearly labelled which constituency boundaries were approximated so that users can exclude them from projects that require higher accuracy, such as tools that help citizens identify their constituency based on their home address.

With these caveats, we are making these datasets available as open data so that others can benefit from Stears’ hundreds of hours of research and data processing. We believe these boundaries are an important contribution towards transparency in Nigeria’s political landscape and will enable many valuable civic-minded projects spanning education, health, and development.

⬇️ Download the data

This data is intended for non-commercial usage only.

Special thanks to our stellar team, who spent many hours diligently producing the datasets: Adewale, Opeyemi, Mayowa, and Damilola.