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[Duncan C]

Originally Posted by coulls

Hi all,

I have a line object made up of two CLLocation's (startPoint and endPoint). I am adding a tolerance set in metres (say 3000 metres) around an MBR (Minimum Bounding Rectangle) derived from these two points.

The question I have is how would I add say 3000 metres to a CLLocation and arrive at a new CLLocation, especially given that there's no function like this?

-(CLLocation *) addDistanceToLocation:(CLLocation*)location:(float)metresLatitude:(float)metresLongitude;

What I'd ideally like to do is something like this:

startPoint = addDistanceToLocation:startPoint:3000:-3000

EDIT: I've changed my MBR code to read like this:

	MBR *mbr = [MBR alloc];
	CLLocation *x1y1 = [[CLLocation alloc] init];
	CLLocation *x2y2 = [[CLLocation alloc] init];
	x1y1.coordinate.latitude = MAX(startPoint.coordinate.latitude, [endPoint.coordinate.latitude]);
	x1y1.coordinate.longitude = MIN(startPoint.coordinate.longitude, [endPoint.coordinate.longitude]);
	x2y2.coordinate.latitude = MIN(startPoint.coordinate.latitude, [endPoint.coordinate.latitude]);
	x2y2.coordinate.longitude = MAX(startPoint.coordinate.longitude, [endPoint.coordinate.longitude]);
	mbr.topLeft = x1y1;
	mbr.bottomRight = x2y2;

Thought it might be easier to work with two CLLocations (topLeft and bottomRight). Still can't see how to add distances to these and arrive at a new set of points.

Thanks,

Jason

I wrestled with this too. You can't change the values in a CLLocation. What you have to do is calculate the new coordinate you want, and then initialize a new one with the parameters from the old one.

You use the call initWithCoordinate:altitude:horizontalAccuracy:ver ticalAccuracy:timestamp: to create a new location using the values from the old location.

That lets you copy most, but not all, of the settings from the old location.


Regards,

Duncan C
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