I use this code in viewWillLayoutSubviews to set the initial region of my map. 

CLLocationCoordinate2D startCoord = CLLocationCoordinate2DMake(13.747266, 100.526804);
MKCoordinateRegion adjustedRegion = [self.mapView regionThatFits:MKCoordinateRegionMakeWithDistance(startCoord, 800, 800)];
[self.mapView setRegion:adjustedRegion animated:YES];
NSLog(@"%f",adjustedRegion.span.latitudeDelta);

However, the initial zoom level doesn't work. The coordinate is correct, but it always zoom in to probably the max level. I check the span of the region and got 0.0. How do I fix this.

ios mkmapview zooming
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