title: MKMapView Zoom and Region
body: <p>I'm familiar with using Google Maps Javascript API. Recently I started using MapKit framework for an iphone project, but I'm having a hard time to figure out zooming and setting a region on map.</p>
  
  <p>In Google Maps API I used to use integer zoom levels like 8, 9, 10 along with straightforward function setZoom(). The only equivalent method I can see in the MapKit framework is setRegion:animated. As I understand, I need to set a region's span's latitude and longitude "delta" values to specify zoom level. But I really don't have an idea what these values represent(I read the documentation).</p>
  
  <p>When I use a MKMapView delegate and trace the span values in regionDidChange delegate method results don't seem to correlate each other. It's ok when I zoom out and see the span delta values are increasing as specified in documentation. But suddenly I drag the map without zooming and delta values become 0.0. </p>
  
  <p>Can somebody please explain what is the reference point to these span and delta? Or is there any algorithm to convert an integer zoom level(like 9) to these delta values? </p>
  
  <p>As a bonus question is there any way to specify a minimum-maximum zoom level on a MKMapView :) </p>
  
  <p>Thanks</p>