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Toward a global urbanization analysis for subnational territories by exploring remote sensing-based products

Hamidreza Zoraghein, Population Council
Leiwen Jiang, Shanghai University and Population Council

World population increasingly lives in urban areas. Each country uses its own criteria to define urbanization level (urban percentage of population). To harmonize global urbanization analysis, the U.N. Statistical Commission endorsed a new methodology called the degree of urbanization and developed by the European Commission. It employs GHS-SMOD, a global satellite product categorizing each 1 km terrestrial cell to seven categories along the rural-urban continuum, based on their population and built-up presence. Studies show derived national urbanization levels using the new methodology may match well those by administrative definitions in some countries, but not so in others. To understand characteristics of GHS-SMOD to underlie globally harmonized urbanization analysis, this paper takes a further step to explore disparities in urbanization levels of subnational units from the two sources. This is important at the subnational level as many countries do not report urbanization records at this level while they matter for regional policy areas including health, housing, transportation, and climate change. Therefore, we compare subnational GHS-SMOD and census-based urbanization levels for a selection of countries. Our analysis reveals different levels of agreement between these two sources, mostly attributable to the urban status and criteria employed by national censuses.

Keywords: Urbanization and urban populations, Remote sensing, Census data, Geographic Information Systems (GIS)

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  Presented in Session 38. New Methods and Measures in Urbanization