MKMapSize
Width and height information on a two-dimensional map projection.
Declaration
struct MKMapSizeOverview
If you project the curved surface of the globe onto a flat surface, what you get is a two-dimensional version of a map where longitude lines appear to be parallel. Such maps are often used to show the entire surface of the globe all at once. An MKMapSize data structure represents a horizontal and vertical distance as measured on this two-dimensional map.