Global Travel Time to Cities and Ports at 1-Kilometre Resolution, 2015

2015 global travel-time accessibility indicators at approximately one-kilometre spatial resolution. The dataset provides estimated land-based travel times in minutes to the nearest city and nearest port, with 12 layers for cities based on population size and 5 layers for ports based on size. Andy Nelson created this suite of validated indicators, which are in GeoTIFF format suitable for Geographic Information Systems.

Use Cases

• Mapping physical access to urban services based on travel-time layers.
• Analyzing spatial inequalities in access for different population segments based on the global coverage.
• Modeling supply chain or trade logistics based on travel time to ports of varying sizes.
• Validating or calibrating other accessibility models using the described methodology and validation.

Strengths

• Global spatial coverage with an extent from -180 to 180 longitude and -60 to 85 latitude.
• High spatial resolution of approximately one kilometre (30 arc seconds).
• Includes 12 distinct data layers for cities and 5 for ports, based on different size thresholds.
• Travel time estimates are validated, as described in the linked Nature Scientific Data Descriptor.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Last update date is unknown; freshness unverified as updates depend on future input availability.
• Data is limited to the year 2015 and land-based travel, excluding other modes or time periods.

Provenance

Source

Andy Nelson, with methodology and validation described in a Nature Scientific Data Descriptor.

Collection Method

Travel time was estimated using an accumulated cost function in the gdistance R package, based on urban areas from the Global Human Settlement Layers and a travel cost surface.

Time Range

2015

Freshness

Temporal resolution is 2015. Updates may follow but are dependent on the availability of updated inputs.

Geography

Global land coverage (approximately -60 to 85 degrees latitude).