Polygons from First Principles: How χGRIDs Extend 2025 UN Settlement Methodology to Neighborhood-Scale Geographies
Skill Level: Beginner, Intermediate
Intended Audience: GIS Builder, GIS Developer, Student
Abstract
Though political units (like wards) are obviously important in policy contexts, oftentimes it can be useful to have a simple and globally reproducible methodology to facilitate comparisons of urban areas. This talk walks through two examples of such methodologies as applied within the Chicago volunteer civic tech project Ward Wise.
Earlier this year, Ward Wise released a new dashboard, Penlight, that visualizes wellbeing in Chicago. (You can try it out yourself at https://penlight.wardwise.org.) Users can select their own preferred geography breakdown, such as ward or neighborhood, but we’ve recently introduced the χGRIDs as a new approach to providing more consistent granularity throughout the city, building upon OSM street data.
Similarly, Ward Wise is now optionally enabling analysis of Chicago within the newly defined 2025 UN urban limits rather than merely its administrative boundaries. These new polygons made headlines for declaring Jakarta as the most populous city in the world, but they can have broad utility by creating a standard and replicable approach that builds upon DEGURBA data and the Global Human Settlement Layer. This talk reviews this methodology and discusses its benefits for global city-level analysis.
Attendees will leave with an understanding of the UN’s 2025 urban area approach, how it differs from the similar-yet-distinct JRC 2023 urban area approach, and how one might apply similar approaches at the neighborhood level.
Presenter
Harry Brisson
Data Lead & Co-Founder, Ward Wise