The world's user-generated road map is more than 80% complete

PLoS One. 2017 Aug 10;12(8):e0180698. doi: 10.1371/journal.pone.0180698. eCollection 2017.

Abstract

OpenStreetMap, a crowdsourced geographic database, provides the only global-level, openly licensed source of geospatial road data, and the only national-level source in many countries. However, researchers, policy makers, and citizens who want to make use of OpenStreetMap (OSM) have little information about whether it can be relied upon in a particular geographic setting. In this paper, we use two complementary, independent methods to assess the completeness of OSM road data in each country in the world. First, we undertake a visual assessment of OSM data against satellite imagery, which provides the input for estimates based on a multilevel regression and poststratification model. Second, we fit sigmoid curves to the cumulative length of contributions, and use them to estimate the saturation level for each country. Both techniques may have more general use for assessing the development and saturation of crowd-sourced data. Our results show that in many places, researchers and policymakers can rely on the completeness of OSM, or will soon be able to do so. We find (i) that globally, OSM is ∼83% complete, and more than 40% of countries-including several in the developing world-have a fully mapped street network; (ii) that well-governed countries with good Internet access tend to be more complete, and that completeness has a U-shaped relationship with population density-both sparsely populated areas and dense cities are the best mapped; and (iii) that existing global datasets used by the World Bank undercount roads by more than 30%.

MeSH terms

  • Cities
  • Databases, Factual
  • Geographic Information Systems*
  • Geographic Mapping*
  • Humans
  • Maps as Topic*
  • Motor Vehicles
  • Satellite Imagery*
  • Transportation Facilities

Grant support

This work was funded by Social Sciences and Humanities Research Council of Canada Award Number: 435-2016-0531 | Recipient: Christopher Barrington-Leigh; Hellman Fellows Program Award Number: None | Recipient: Adam Millard-Ball; and UC Santa Cruz Committee on Research Award Number: None | Recipient: Adam Millard-Ball. None of these funders had any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.