Route Match Extension API Developer's Guide

Route Gaps and Ignored Trace Points

Traces may contain bad GPS points that are either at 0/0 or far away from the trace path or – although not far away from the trace path – would require a large detour to be included in the route path. Route Match Extension API ignores them when creating the most probable route path, but afterwards matches them onto the route path, indicating the issues by warnings and by a low point match confidence value. This way Route Match Extension API always provides the most probable path as a fully connected route (without gaps) and matches all the trace points to their most probable place along this route.

Traces may traverse gaps in the HERE road network. This is due to gaps or errors in the HERE map, vehicles or persons using paths that are outside the HERE map inclusion rules such as unofficial or private roads and/or paths, or vehicles and/or persons that use transport types such as walking, train, boat or airplanes that do not follow HERE roads.

If that leads to few outlier points along an otherwise reasonable path, then Route Match Extension API ignores them when creating the route path, as described above. If it leads to gaps on an otherwise reasonably matched road path, then Route Match Extension API includes detours to aovid the gaps. Route links on such detours have a low link match confidence value so it is easy to apply – depending on the use case – thresholds to treat these detours appropriately, for example to skip them for driver rating, since the driver most probably did not drive there. So Route Match Extension API guarantees to provide a fully connected route without gaps, while it is easy for applications to detect and handle the situation appropriately, and "create" the gaps from the link match confidence values.