GreatCircle is an iOS framework that provides a set of extensions to the CLLocation class.

The CLLocation class provides only one method:

- (CLLocationDistance)distanceFromLocation:(const CLLocation *)location

For calculating the distance between two GPS locations. Because of this, iOS developers must "roll their own" to solve more complex GPS location calculation problems.

GreatCircle - which is based on the amazing work of Chris Veness, the owner of the Geodesy functions project - provides a comprehensive set of extension methods to the CLLocation class that make working with GPS locations and performing calculations on then simple and easy.

(For a more general introduction, see: Movable Type Scripts Latitude / Longitude Calculations Reference)

Thus far, I have worked on porting the spherical-earth model, which provides simple formulae covering the accuracy requirements of most use cases.

• Getting Started
• Documentation
• Code of Conduct
• Contributing
• License

GreatCircle should be used via Carthage dependency manager. (Why no Cocoapod? I've switched my work to Carthage. Here's why.)

github "softwarenerd/GreatCircle" "master"

(Until GreatCircle is released, there are no tagged versions, so please use the master branch.)

carthage update

Add a run script that uses the carthage copy-frameworks command to copy the GreatCircle.framework

Extension Methods

-crossTrackDistanceToStartLocation:endLocation:
Returns the cross track distance (in meters) of this location relative to the specified start location and end location.

-crossTrackLocationToStartLocation:endLocation:
Returns a location representing the cross track point of this location relative to the specified start location and end location.

-distanceToOtherLocation:
Returns the distance (in meters) between this location and the other location.

-finalBearingToOtherLocation:
Returns the final bearing (in degrees) between this location and the other location. The final bearing is the initial bearing from the other location to this location reversed 180°. The final bearing will differ from the initial bearing by varying degrees according to distance and latitude.

-initialBearingToOtherLocation:
Returns the initial bearing (in degrees) between this location and the other location.

+intersectionOfLocation:andBearing:withLocation:andBearing:
Returns a location representing the point of intersection of two paths, each specified by a location and bearing. Returns nil if the two paths do not cross.

-isEqualToOtherLocation:
Compares this location to the other location for equality.

-locationWithBearing:distance:
Returns a location representing the point that lies at the specified bearing and distance from this location.

-midpointToOtherLocation:
Returns a location representing the midpoint between this location and the other location.

GreatCircle is a work in progress and your contributions are most welcome. Feel free to fork the repo and submit PR's.

GreatCircle is released under the MIT License.