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. 2019 Nov 7;6(1):266.
doi: 10.1038/s41597-019-0265-5.

A suite of global accessibility indicators

Andy Nelson  1 , Daniel J Weiss  2 , Jacob van Etten  3 , Andrea Cattaneo  4 , Theresa S McMenomy  4 , Jawoo Koo  5
Affiliations

A suite of global accessibility indicators

Andy Nelson et al. Sci Data. .

Abstract

Good access to resources and opportunities is essential for sustainable development. Improving access, especially in rural areas, requires useful measures of current access to the locations where these resources and opportunities are found. Recent work has developed a global map of travel times to cities with more than 50,000 people in the year 2015. However, the provision of resources and opportunities will differ across the broad spectrum of settlements that range from small towns to megacities, and access to this spectrum of settlement sizes should also be measured. Here we present a suite of nine global travel-time accessibility indicators for the year 2015, at approximately one-kilometre spatial resolution, for a range of settlement size classes. We validated the travel-time estimates against journey times from a Google driving directions application across 1,511 2° × 2° tiles representing 47,812 journeys. We observed very good agreement, though our estimates were more frequently shorter than those from the Google application with a median difference of -13.7 minutes and a median percentage difference of -16.9%.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
The overlapping processing zones. The map shows the 25 overlapping zones that were used for processing. Another 11 zones were generated that cross the antemeridian (not shown). Country boundaries are from GADM v3.6.
Fig. 2
Fig. 2
Global accessibility layers. Maps show travel time to the nearest human settlement in the year 2015 for three of the nine accessibility layers, (a) for settlement class 1 (>=5,000,000 and <50,000,000 people), (b) for settlement class 5 (>=100,000 and <200,000 people), and (c) for settlement class 9 (>=5,000 and <10,000 people). Country boundaries are from GADM v3.6.
Fig. 3
Fig. 3
Validation outputs. (a) Difference in estimates in minutes (our estimates − Google journey times), (b) percentage difference in estimates (100 × [our estimates − Google journey times]/Google journey times), (c) histogram of difference in minutes, (d) histogram of percentage difference. Panels a and c, and panels b and d have the same colour schemes. Country boundaries are from GADM v3.6.
See this image and copyright information in PMC

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