How to get radius from visible area of MKmapview?

Question

I am able to get visible rectangle of map view and also centre point of map view and span deltas are also get from mkmaap view methods: To get visible are :mapView.vis

Answer 1

To get the radius follow this:

- (CLLocationDistance)getRadius
{
    CLLocationCoordinate2D centerCoor = [self getCenterCoordinate];
    // init center location from center coordinate
    CLLocation *centerLocation = [[CLLocation alloc] initWithLatitude:centerCoor.latitude longitude:centerCoor.longitude];

    CLLocationCoordinate2D topCenterCoor = [self getTopCenterCoordinate];
    CLLocation *topCenterLocation = [[CLLocation alloc] initWithLatitude:topCenterCoor.latitude longitude:topCenterCoor.longitude];

    CLLocationDistance radius = [centerLocation distanceFromLocation:topCenterLocation];

    return radius;
}

It will return the radius in metres.

To get center coordinate

- (CLLocationCoordinate2D)getCenterCoordinate
{
    return [self.mapView centerCoordinate];
}

For getting radius, depends on where you want to get the 2nd point. Lets take the Top Center

- (CLLocationCoordinate2D)getTopCenterCoordinate
{
    // to get coordinate from CGPoint of your map
    return [self.mapView convertPoint:CGPointMake(self.mapView.frame.size.width / 2.0f, 0) toCoordinateFromView:self.mapView];
}