Question

Can anyone point me in the right direction when it comes to understanding MKMapPoint?

I understand that it has to do with laying suface of the globe on a 2D surface. But I don’t understand how each “point” is measured?

Can anyone give me an example in code?

Answer 1

There is nothing much to it.. just a structure to display point on a 2D map… here is what the documentation says..

MKMapPoint A point on a two-dimensional map projection.

typedef struct {
double x;
double y; } MKMapPoint;

Fields x The location of the point along the x-axis of the
map. y The location of the point along the y-axis of
the map. Discussion 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
MKMapPoint data structure represents a point on this two-dimensional
map.

The actual units of a map point are tied to the underlying units used
to draw the contents of an MKMapView, but you should never need to
worry about these units directly. You use map points primarily to
simplify computations that would be complex to do using coordinate
values on a curved surface. By converting to map points, you can
perform those calculations on a flat surface, which is generally much
simpler, and then convert back as needed. You can map between
coordinate values and map points using the MKMapPointForCoordinate and
MKCoordinateForMapPoint functions.

When saving map-related data to a file, you should always save
coordinate values (latitude and longitude) and not map points.

Availability Available in iOS 4.0 and later. Declared In MKGeometry.h