Pre-loading waypoint data

摘要

A method of downloading map data to a portable electronic device entails determining a route, identifying waypoints along the route, and downloading and caching map data for the waypoints along the route. The map data for areas around each of the waypoints (intersections, decision points) are thus preloaded prior to the device arriving at or near each waypoint. This ensures that the device has locally cached all the map data needed to render a navigationally useful map of the area around each waypoint.

主权项

1. A method, performed by a portable electronic device, of downloading map data to the portable electronic device, the method comprising:
determining, by a processor, a route; identifying navigationally significant waypoints along the route where navigation decisions are to be made; prioritizing map tiles for download based on a proximity of each waypoint to the device; and downloading and caching map data for one or more prioritized map tiles corresponding to the waypoints along the route.