accumulating distance

gistfile1.m

// The Core Location example in Beginning iPhone 4 Development shows how to
// calculate a distance from a starting point, but it doesn't show how far you've
// actually traveled. These changes should let you see an accumulated distance.

// Add this to the interface declaration in WhereAmIViewController.h:

    CLLocationDistance totalDistance;

// then replace the last chunk of locationManager:didUpdateToLocation:fromLocation:
// with this:

    CLLocationDistance distance = [newLocation distanceFromLocation:startingPoint];
    totalDistance += distance;
    NSString *distanceString = [[NSString alloc] initWithFormat:@"%gm", totalDistance];
    distanceTraveledLabel.text = distanceString;
    [distanceString release];
    self.startingPoint = newLocation;