How to Specify the Exact Region on the Map in IOS

Question

I have create a zone on the map and save this coordinate and current zoom level in the database. When we edit this zone and open the map in the mapkit with the same coordinate and zoomlevel region on the map shown is different what we have created.

  CLLocationCoordinate2D cd= CLLocationCoordinate2DMake(30.724300, 76.723166);
MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(cd, 4640, 4565);
[self.mapView setRegion:viewRegion animated:YES];

Using this function I get the region width and height

   -(void) getMapDelta:(CLLocationCoordinate2D) coord
 {
MKCoordinateSpan span = self.mapView.region.span;
CLLocationCoordinate2D loc = self.mapView.region.center;
//get latitude in meters
CLLocation *loc1 = [[CLLocation alloc] initWithLatitude:(self.mapView.region.center.latitude - span.latitudeDelta * 0.5) longitude:self.mapView.region.center.longitude];
CLLocation *loc2 = [[CLLocation alloc] initWithLatitude:(self.mapView.region.center.latitude + span.latitudeDelta * 0.5) longitude:self.mapView.region.center.longitude];
//get longitude in meters
CLLocation *loc3 = [[CLLocation alloc] initWithLatitude:self.mapView.region.center.latitude longitude:(self.mapView.region.center.longitude - span.longitudeDelta * 0.5)];
CLLocation *loc4 = [[CLLocation alloc] initWithLatitude:self.mapView.region.center.latitude longitude:(self.mapView.region.center.longitude + span.longitudeDelta * 0.5)];
int metersLatitude = [loc1 distanceFromLocation:loc2];
int metersLongitude = [loc3 distanceFromLocation:loc4];
NSLog(@"Delta> %d / %d", metersLongitude,metersLatitude);
NSLog(@"Coor> %f / %f", coord.latitude,coord.longitude);

}