Data Science Day @ Columbia University

Launched in 2004, OpenStreetMap (OSM) is the largest collaborative project to date to create free and editable cartographic data of the world. This study aims to validate quality aspects of road features in OSM such as positional accuracy, completeness, and lineage in four West African countries. A series of test diagnostics integrates statistical and spatial analysis to measure positional accuracy at road intersections against satellite imagery from Google Earth; completeness via discrete classification, spatial regression, and inter-settlement connectivity analyses; and finally, lineage by comparing versioning of road features against positional accuracy results. All the analysis is conducted in R and ArcGIS. This work was completed by CIESIN, a unit of the Earth Institute at Columbia University, under the CODATA Task Group for Global Roads Data Development.