Search for: All records

Cost-surface analyses in geographic information systems (GIS) can be a useful tool for approximating the travel of historic sailing ships to fill gaps in the historic record. We present the Global-TRANSIT workflow, a least-cost surface raster analysis that uses wind speed and direction to estimate sailing routes and durations for ports globally. Our workflow, freely available as a Python notebook for ArcGIS Pro, makes three contributions relative to previously published toolkits. First, our workflow estimates sail travel for ports at the global scale while accounting for projection-related challenges. Second, our workflow evaluates origin and destination pairs in a many-origins-to-many-destinations matrix structure (compared to previous one-origin-to-one-destination relationship) which increases the scalability of our toolbox. Third, our workflow replaces the deprecated tools used in the previous work with newer tools that reduce the grid-induced bias. Despite the expected limitations of modeling a complex phenomenon like sailing, we find a high correlation between our modeled estimates and historically observed sail duration and routes. The outputs of Global-TRANSIT provide an approximation of the likely duration and route of sail travel between worldwide ports, serving as a reference for understanding historic sail voyage patterns globally and as a benchmark for measuring the evolution of maritime shipping over time.