How do you use 'MapKit' and 'CoreLocation' to display and interact with geographical data in an iOS app?

Official answer

MapKit displays maps, annotations and overlays, and can request directions. Core Location supplies device location and related authorization/state. A map of supplied coordinates can work without asking for the person's location; request location only when the feature needs it.

For a nearby-places feature, provide the required usage description, explain the benefit at the point of use and request the least access needed, usually When in Use. Handle not-determined, denied, restricted and changed authorization. Offer manual place entry or browsing when access is unavailable. Account for reduced accuracy, stale timestamps and unsuitable accuracy rather than treating every coordinate as a precise current fix.

Retain and configure the location manager according to the chosen API, stop unnecessary updates, and choose accuracy/update behavior that fits the task and battery cost. Always authorization and background modes are separate requirements and do not imply unrestricted continuous execution.

Display validated coordinates through annotations and regions. For route requests, supply source, destination and transport options to MKDirections, handle asynchronous errors or no route, and ignore results belonging to an obsolete request. Render the returned route with a suitable overlay and present its estimate as an estimate. Getting a route polyline is not a complete turn-by-turn navigation system.

Test denial, authorization changes, approximate location, offline/error states, missing routes and rapid destination changes. Keep precise location out of unnecessary logs, minimize retention and make any sharing explicit. Only claim behavior tested on the supported OS/device and service conditions.

Location permission and lifecycle, Directions request and throttling