Global high-Resolution Updatable Friction Surface (GRUFS): production and validation code

This code archive contains the production and validation scripts used to generate the Global high-Resolution Updatable Friction Surface (GRUFS) datasets. The production workflow prepares OpenStreetMap roads, ferries, perennial water features, land cover, elevation, slope, and country-road-surface lookup inputs, then generates two global 30 m raster friction surfaces: GRUFS Foot and GRUFS Mixed. The validation workflow compares GRUFS travel-time estimates against external routing and friction-surface comparators, constructs enriched origin-destination validation linework, and produces the statistical summaries and graphics reported in the associated manuscript.

The workflow was implemented in Python using ArcPy from Esri ArcGIS Pro and requires a licensed ArcGIS Pro installation with the Spatial Analyst extension. OpenStreetMap extraction requires osmium-tool. Google routing validation requires a user-provided Google Maps API key. The scripts are archived for transparency and reproducibility and require users to update local file paths before execution.