LocationHandler.swift

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [AnyObject]) {
        let location = locations.lastObject as! CLLocation
        if let lastLocation = lastGeocodedLocation {
            if lastLocation.distanceFromLocation(location) < distanceFilter {
                NSLog("current location is within \(round(distanceFilter))m of previous location")
                return
            }
            if abs(location.coordinate.latitude - lastLocation.coordinate.latitude) < lastLocation.horizontalAccuracy &&
                abs(location.coordinate.longitude - lastLocation.coordinate.longitude) < lastLocation.verticalAccuracy {
                    var distance = sqrt(pow(lastLocation.horizontalAccuracy,2) + pow(lastLocation.verticalAccuracy,2))
                    NSLog("current location is within accuracy=\(round(distance))m of previous location")
                    return
            }
        }
        // TODO throttle frequency
        lastGeocodedLocation = location
        locationManager.allowDeferredLocationUpdatesUntilTraveled(10, timeout:15*60)
        geocoder.reverseGeocodeLocation(location) {(placemarks, error) in
            if error != nil {
                NSLog("%@", error)
                return
            }
            let place = placemarks.first as CLPlacemark
            self.delegate?.locationManager?(self, didUpdatePlacemark: place, location: location)
            self.locationUploader?.locationManager?(self, didUpdatePlacemark: place, location: location)
        }
    }