Documentation v0.3.0
DDL Global Urban Boundaries
City polygons with stable identifiers, published globally.
Coverage and granularity#
Every parent city with a population of at least 50,000.
9,849 of 9,849 parent cities · static · 13,366 rows across the package
- City: 9,849 of 9,849 boundary IDs
- ADM1: 387 of 387 boundary IDs
- ADM2: 3,130 of 3,130 boundary IDs
Row key: id
Examples in the Boundary Explorer: Guangzhou, Dallas, Athens.
Joining this data#
A Python example using GeoPandas and pandas. Replace the file paths with your local downloads. See boundary levels and join keys.
import geopandas as gpd
import pandas as pd
# Match the boundary file to the module's geographic level.
level = "PARENT"
boundaries = gpd.read_file("parent.gpkg")
observations = pd.read_parquet("ddl-population-historical.parquet")
observations = observations.loc[observations["boundary_level"].eq(level)]
joined = boundaries.merge(
observations, on="id", how="left", validate="one_to_many"
)
print(joined.head())Before you use this#
- area is computed on the geography type, in square metres, not in the layer's own projected units.
- Hong Kong publishes under CHN, because the boundaries carry it that way.
Schema#
| Name | Type | Units | Description |
|---|---|---|---|
id | string | — | City identifier. Stable across releases. |
name | string | — | City name. |
population | int64 | people | Estimated population of the city. |
alpha3 | string | — | ISO 3166-1 alpha-3 country code. |
area | float64 | m² | Geometry area in square meters. |
geometry | geometry | — | Urban boundary polygon. Coordinate system: EPSG:4326. |
Notes#
- The parent city is the reference geography for the city profile. Its identifier connects the published tables.
- ADM1 and ADM2 files contain released administrative intersections of qualifying parent polygons. Published splits may not cover the whole parent; do not assume their measures sum to parent totals. Use the split identifier for split-level measures and parent_id to relate a split to its parent.
- GHSL and GADM map overlays provide comparison geographies. They do not change the boundaries used to calculate the profile measures.
Citation#
When using these data, cite Urban Growth Center and the original source below, where applicable.
Urban Growth Center
Citation
Development Data Lab. (2026). Urban Growth Center. https://cities.devdatalab.org/
Further reading#
Methodology paper Coming soon