Geofencing in iOS with Swift
Geofencing is a capability which allows your app to be notified when its device enters user-defined geographical regions.
Just recently, I wrote a tutorial on how to implement geofencing in iOS with Swift, using the Region Monitoring API in Core Location. The tutorial will guide you through the creation of a location-based reminder app that will let the user create reminders and associate them with real-world locations.
Check out the tutorial post at RayWenderlich.