An Interactive System to Compare, Explore and Identify Discrepancies across Map Providers.

All online map service providers are working hard to maintain high-quality maps to provide high-quality services. Example inaccuracies that can be encountered in the provided maps may include missing road segments, shifted road segments, missing road connections, missing or incorrect turn restrictions, and mislabeling road attributes like marking a directional road as one-way. Maps may also be rapidly changing in some areas due to new constructions. While the accuracy of various mapping systems, as given by service providers, is known to be high, even the minor discrepancies in the underlying maps may lead to unsatisfactory user experience in routing and location-based services.In this paper, we present a system that compares the routes returned by the public APIs of some major routing engines, namely Bing Maps, Google Maps, and OpenStreetMap. The system highlights the differences in the proposed routes between these routing engines, given the same start/end points for a planned trip. The route differences are examined based on travel distance, travel duration, and route geometry. The system can also enforce a routing engine to take the same route as another routing engine to identify the possible discrepancies in the underlying mapping system of each routing engine. The system identifies and categorizes the discovered discrepancies, across various engines, in (1) the geometry of the road segments, (2) the connectivity and turn restrictions of the Road Network Graph (RNG), and (3) the attributes of the road segments. The presented system is currently in pilot use by a group of professional editors to support their daily work of identifying, visually inspecting, and interactively trying alternative corrections to the underlying RNGs in various parts of the globe. This helps us develop the system's capabilities even further based on their continuous feedback in real usage scenarios.