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  1. PO
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    <p>Usually a rectangle doesn't have a radius, a circle has. So I guess you meant 'side of a square' because you actually want to draw a square?</p> <p>You need to calculate the 4 coordinates of your square's corners. </p> <pre><code>- (void) addSquareToMap:(CLLocation*)center withRadius:(float)radius{ // Create a C array of size 4 CLLocationCoordinate2D points[4]; //Fill the array with the four corners (center - radius in each of four directions) points[0] = CLLocationCoordinate2DMake(center.coordinate.latitude-radius, coord.longitude-radius); points[1] = CLLocationCoordinate2DMake(center.coordinate.latitude+radius, coord.longitude-radius); points[2] = CLLocationCoordinate2DMake(center.coordinate.latitude+radius, coord.longitude+radius); points[3] = CLLocationCoordinate2DMake(center.coordinate.latitude-radius, coord.longitude+radius); //Create the polygon MKPolygon* poly = [MKPolygon polygonWithCoordinates:points count:4]; poly.title = @"Square"; // Add it to the map [map addOverlay:poly]; } - (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id &lt;MKOverlay&gt;)overlay{ if ([overlay isKindOfClass:[MKPolygon class]]){ MKPolygonView* aView = [[[MKPolygonView alloc] initWithPolygon:(MKPolygon*)overlay] autorelease]; aView.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.15]; aView.strokeColor = [[UIColor redColor] colorWithAlphaComponent:0.7]; aView.lineWidth = 3; return aView; } return nil; </code></pre> <p>}</p> <p>EDIT: Sorry I misread the "meters" portion of your question, so here is a more simple answer.</p> <pre><code>- (void) addSquareToMap:(CLLocation*)center withRadius:(float)radius{ MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(center.coordinate, radius*2, radius*2); CLLocationCoordinate2D points[4]; //Fill the array with the four corners (center - span/2 in each of four directions) points[0] = CLLocationCoordinate2DMake(region.center.latitude - region.span.latitudeDelta/2, region.center.longitude - region.span.longitudeDelta/2); points[1] = CLLocationCoordinate2DMake(region.center.latitude + region.span.latitudeDelta/2, region.center.longitude - region.span.longitudeDelta/2); points[2] = CLLocationCoordinate2DMake(region.center.latitude + region.span.latitudeDelta/2, region.center.longitude + region.span.longitudeDelta/2); points[3] = CLLocationCoordinate2DMake(region.center.latitude - region.span.latitudeDelta/2, region.center.longitude + region.span.longitudeDelta/2); MKPolygon *polygon = [MKPolygon polygonWithCoordinates:points count:4]; polygon.title = @"Square"; // Add it to the map [self.mapView addOverlay:polygon]; } - (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id &lt;MKOverlay&gt;)overlay{ if ([overlay isKindOfClass:[MKPolygon class]]){ MKPolygonView* aView = [[[MKPolygonView alloc] initWithPolygon:(MKPolygon*)overlay] autorelease]; aView.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.15]; aView.strokeColor = [[UIColor redColor] colorWithAlphaComponent:0.7]; aView.lineWidth = 3; return aView; } return nil; } </code></pre> <p>You can easily test it with the MapCallouts example by replacing the allAction method with:</p> <pre><code>- (IBAction)allAction:(id)sender{ //CLLocationCoordinate2D SF = CLLocationCoordinate2DMake(37.786996, -122.440100) ; CLLocation *center = [[CLLocation alloc] initWithLatitude:37.786996 longitude:-122.440100]; [self addSquareToMap:center withRadius:1000]; } </code></pre>
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    1. POMKPolygon from Point + Radius/Distance (iPhone SDK)
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    1. USCyril Godefroy
    1. USCyril Godefroy
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    1. COI added an image to describe the problem. With your calculation the rect is too large.
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    2. COWhat is radius in your solution? If radius is the CLLocationDistance (meters) the points are wrong.
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    3. COI didn't notice you used CLLocationDistance for the radius. Seems rather counter intuitive to me. Sorry about that.
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      1. USCyril Godefroy
 

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