Longitude, Latitude to XY coordinate conversion

Question

I want to now how to convert longitude, latitude to its equivalent xy coordinate components in iPhone programming. (I am using only CoreLocation programming, and want to show a

Answer 1

Well the exact conversion depends on exactly which part of the Earth you want to show, and the stretching along longitude varies according to latitude, at least in Mercator.

That being said, even if you don't want to display an actual MapKit map, it would probably be easiest to create an MKMapView and keep it to one side. If you set the area you want to display appropriately on that (by setting the region property), you can use convertCoordinate:toPointToView: to map from longitude and latitude to a 2d screen location.

Note that MKMapView adjusts the region you set so as to make sense for the viewport its been given (eg, if you gave it a region that was a short fat rectangle, but the view it had was a tall thin rectangle, it'd pick the smallest region that covers the entire short fat rectangle but is the shape of a tall thin rectangle), so don't get confused if you specify a region with the top left being a particular geolocation, but then that geolocation isn't at the exact top left of the view.