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    <p>Create <code>MKMapView+ZoomLevel.h</code> as</p> <pre><code>#import &lt;MapKit/MapKit.h&gt; @interface MKMapView (ZoomLevel) - (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel animated:(BOOL)animated; @end </code></pre> <p>Create <code>MKMapView+ZoomLevel.m</code> as</p> <pre><code>#import "MKMapView+ZoomLevel.h" #define MERCATOR_OFFSET 268435456 #define MERCATOR_RADIUS 85445659.44705395 @implementation MKMapView (ZoomLevel) #pragma mark - #pragma mark Map conversion methods - (double)longitudeToPixelSpaceX:(double)longitude { return round(MERCATOR_OFFSET + MERCATOR_RADIUS * longitude * M_PI / 180.0); } - (double)latitudeToPixelSpaceY:(double)latitude { return round(MERCATOR_OFFSET - MERCATOR_RADIUS * logf((1 + sinf(latitude * M_PI / 180.0)) / (1 - sinf(latitude * M_PI / 180.0))) / 2.0); } - (double)pixelSpaceXToLongitude:(double)pixelX { return ((round(pixelX) - MERCATOR_OFFSET) / MERCATOR_RADIUS) * 180.0 / M_PI; } - (double)pixelSpaceYToLatitude:(double)pixelY { return (M_PI / 2.0 - 2.0 * atan(exp((round(pixelY) - MERCATOR_OFFSET) / MERCATOR_RADIUS))) * 180.0 / M_PI; } #pragma mark - #pragma mark Helper methods - (MKCoordinateSpan)coordinateSpanWithMapView:(MKMapView *)mapView centerCoordinate:(CLLocationCoordinate2D)centerCoordinate andZoomLevel:(double)zoomLevel { NSLog(@"in custom zoomlevel--&gt;%f",zoomLevel); // convert center coordiate to pixel space double centerPixelX = [self longitudeToPixelSpaceX:centerCoordinate.longitude]; double centerPixelY = [self latitudeToPixelSpaceY:centerCoordinate.latitude]; // determine the scale value from the zoom level double zoomExponent = 20.0 - zoomLevel; double zoomScale = pow(2, zoomExponent); // scale the map’s size in pixel space CGSize mapSizeInPixels = mapView.bounds.size; double scaledMapWidth = mapSizeInPixels.width * zoomScale; double scaledMapHeight = mapSizeInPixels.height * zoomScale; // figure out the position of the top-left pixel double topLeftPixelX = centerPixelX - (scaledMapWidth / 2); double topLeftPixelY = centerPixelY - (scaledMapHeight / 2); // find delta between left and right longitudes CLLocationDegrees minLng = [self pixelSpaceXToLongitude:topLeftPixelX]; CLLocationDegrees maxLng = [self pixelSpaceXToLongitude:topLeftPixelX + scaledMapWidth]; CLLocationDegrees longitudeDelta = maxLng - minLng; // find delta between top and bottom latitudes CLLocationDegrees minLat = [self pixelSpaceYToLatitude:topLeftPixelY]; CLLocationDegrees maxLat = [self pixelSpaceYToLatitude:topLeftPixelY + scaledMapHeight]; CLLocationDegrees latitudeDelta = -1 * (maxLat - minLat); // create and return the lat/lng span MKCoordinateSpan span = MKCoordinateSpanMake(latitudeDelta, longitudeDelta); return span; } #pragma mark - #pragma mark Public methods - (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel animated:(BOOL)animated { // clamp large numbers to 28 zoomLevel = MIN(zoomLevel, 28); // use the zoom level to compute the region MKCoordinateSpan span = [self coordinateSpanWithMapView:self centerCoordinate:centerCoordinate andZoomLevel:zoomLevel]; MKCoordinateRegion region = MKCoordinateRegionMake(centerCoordinate, span); // set the region like normal [self setRegion:region animated:animated]; } @end </code></pre> <p><code>#import "MKMapView+ZoomLevel.h"</code> statement in your view controller where MKMapView is taken.</p> <pre><code>- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated { double zoomLevel = [self getZoomLevel]; [lblCurrentLevel setText:[NSString stringWithFormat:@"%.2f",zoomLevel]]; NSLog(@"zoomlevel--&gt;%f long--&gt;%f lat--&gt;%f",zoomLevel,mapView.region.span.longitudeDelta,mapView.region.span.latitudeDelta); } - (double) getZoomLevel { return 21.00 - log2(objMapView.region.span.longitudeDelta * MERCATOR_RADIUS * M_PI / (180.0 * objMapView.bounds.size.width)); } </code></pre> <p>In above methods you can get zoom levels as desired, the only thing you have to do is maintain initial zoom and compare latest zoom in/out with that and assign again to that variable.</p> <p>In case of any query let me know we will work out on that :D</p> <p><strong>Edit</strong></p> <p>This source code is from <a href="http://troybrant.net/blog/2010/01/set-the-zoom-level-of-an-mkmapview/" rel="noreferrer">Troy's</a> Blog. Apologize for not mentioning before. </p>
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    1. POHow to detect that MKMapView is zoomed out/in?
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    1. USJanak Nirmal
    1. USJanak Nirmal
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    1. CO@thank you Jennis, I will apply it then will inform you, can I have direct contact to you?
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      1. USChatar Veer Suthar
    2. COlet me know as you read this comment, I am waiting for you.
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      1. USChatar Veer Suthar
    3. COThere actually is an off-by-one error in coordinateSpanWithMapView. To calculate the zoomExponent, you must subtract from 21, not 20; getZoomLevel is correct.
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      1. USRobert Altman
 

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