How to display an image on a MKOverlayView?

Question

UPDATE:

Images who are projected on the MKMapView using a MKOverlayView use the Mercator projection, while the image that I use as input data uses

Answer 1

Your image/overlay is most likely no longer proportional (i.e. it's been stretched). I've seen this kind of thing in my own app where the center of the view is correct, but as you go away from the equator toward either pole (top and bottom of screen) the map/overlay becomes increasingly distorted.

You are obviously scaling your image by scaleFactor. I'd take a look at that for starters.

size_t width    = (CGImageGetWidth(imageReference) / self.scaleFactor);
size_t height   = (CGImageGetHeight(imageReference) / self.scaleFactor);

Another good way to test your code to see if scaling is the culprit, is to scale your MKMapView down to the size of the overlay image. Leave the overlay image alone, and if it is no longer distorted then you know that is the problem.