DP14129 Delineating urban areas using building density

Author(s): Pierre-Philippe Combes, Marie-Pierre De Bellefon, Gilles Duranton, Laurent Gobillon, Clément Gorin
Publication Date: November 2019
Keyword(s): Dartboard approach, Jaccard indices, Urban area definition
JEL(s): C14, R12, R14
Programme Areas: International Trade and Regional Economics
Link to this Page: cepr.org/active/publications/discussion_papers/dp.php?dpno=14129

We develop a new dartboard methodology to delineate urban areas using detailed information about building location, which we implement using a map of all buildings in France. For each pixel, our approach compares actual building density after smoothing to counterfactual smoothed building density computed after randomly redistributing buildings. We define as urban any area with statistically significant excess building density. Within urban areas, extensions to our approach allow us to distinguish 'core' urban pixels and detect centres and subcentres. Finally, we develop novel one- and two-sided tests that provide a statistical basis to compare maps with different delineations, which we use to assess the robustness of our approach and to document large differences between our preferred delineation and the corresponding official one.