Defining City Boundaries for Robust Urban Scaling Analyses

Determine a rigorous, reproducible, and widely applicable methodology for delineating city boundaries to resolve the uncertainty over where a city begins and ends and to mitigate the sensitivity of urban scaling exponent estimates to boundary definitions in empirical urban scaling studies.

Background

In the critique of urban scaling, the authors emphasize that estimated scaling exponents depend on how a “city” is defined spatially. Ambiguity in delineating urban boundaries undermines comparability and can even change the apparent scaling regime of a metric.

They note that although cities are recognizable, their exact spatial limits are not straightforward to define, and prior work has shown that different delineation criteria can yield different scaling exponents and regimes. Establishing a clear, generalizable boundary definition is therefore essential for consistent measurement and interpretation of urban scaling.

References

A recurrent and more pragmatic critical point is the dependence of the estimated scaling exponent value on the definition of a city. Although we can easily identify a city by sight, it is not clear where its boundaries begin and end.

— Urban Scaling Laws  (2404.02642 - Ribeiro et al., 2024) in Section 6 (Criticism)

City definition itself is still a rather open problem, especially at the global scale.

— Removing Population Size, World Cities Leave on Land a Footprint of Wealth  (2608.18792 - Vignolles et al., 19 Aug 2026) in Introduction, paragraph beginning “In this context, the spatial aspects of urban land use...”