CLLocation を使用しても精度が得られません
CLLocation *locA = [[CLLocation alloc] initWithLatitude:CurrentUserLocationNow.latitude longitude:CurrentUserLocationNow.longitude];
locB = [[CLLocation alloc] initWithLatitude:newLocation.coordinate.latitude longitude:newLocation.coordinate.longitude];
distance = [locA distanceFromLocation:locB];
int feet = distance*3.28084;
if(feet >= 40)
{
[avaudioplayer stop];
}
しかし、私は完全な精度を得ていません