CLCircularRegion Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/CoreLocation.framework
Availability
Available in iOS 7.0 and later.
Companion guide
Declared in
CLCircularRegion.h

Overview

The CLCircularRegion class defines the location and boundaries for a circular geographic region. You can use instances of this class to define geo fences for a specific location. The crossing of a geo fence’s boundary causes the location manager to notify its delegate.

Tasks

Initializing a Circular Region

Accessing a Region’s Attributes

Hit Testing in a Region

Properties

center

The center point of the geographic area. (read-only)

@property (readonly, nonatomic) CLLocationCoordinate2D center
Availability
  • Available in iOS 7.0 and later.
Declared In
CLCircularRegion.h

radius

The radius (measured in meters) that defines the geographic area’s outer boundary. (read-only)

@property (readonly, nonatomic) CLLocationDistance radius
Availability
  • Available in iOS 7.0 and later.
Declared In
CLCircularRegion.h

Instance Methods

containsCoordinate:

Returns a Boolean value indicating whether the geographic area contains the specified coordinate.

- (BOOL)containsCoordinate:(CLLocationCoordinate2D)coordinate;
Parameters
coordinate

The coordinate to test against the region.

Return Value

YES if the coordinate lies within the region’s boundaries or NO if it does not.

Availability
  • Available in iOS 7.0 and later.
Declared In
CLCircularRegion.h

initWithCenter:radius:identifier:

Initializes and returns a region object defining a circular geographic area.

- (id)initWithCenter:(CLLocationCoordinate2D)center radius:(CLLocationDistance)radius identifier:(NSString *)identifier;
Parameters
center

The center point of the geographic region to monitor.

radius

The distance (measured in meters) from the center point of the geographic region to the edge of the circular boundary.

identifier

A unique identifier to associate with the region object. You use this identifier to differentiate regions within your application. This value must not be nil.

Return Value

An initialized region object.

Discussion

When defining a geographic region, remember that the location manager does not generate notifications immediately upon crossing a region boundary. Instead, it applies time and distance criteria to ensure that the crossing was intended and should genuinely trigger a notification. So choose a center point and radius that are appropriate and give you enough time to alert the user. For more information, see the information about region monitoring in Location and Maps Programming Guide.

Availability
  • Available in iOS 7.0 and later.
Declared In
CLCircularRegion.h