title: Google maps distance based on the zoom level
body: <p>I have used google maps for displaying some locations using markers, based on the user's current location. User's current location is the center point of the map. The default <code>zoom level</code> is <code>12</code>. In default, I displayed markers within 300 miles(approximately in my case) distance only.</p>
  
  <p>In that how can I do the following,</p>
  
  <p>1) If <code>decrease</code> the zoom level, I need to increase the distance that should display markers within the increased distance also. how much distance should I increase in miles (i.e. <code>Zoom level</code> is <code>11</code>) ?</p>
  
  <p>2) If <code>increase</code> the zoom level, I need to decrease the distance that should display markers without the increased distance. how much distance should I decrease in miles (i.e. <code>Zoom level</code> is <code>13</code>) ?</p>
  
  <p>Please suggest me there is any built-in option to do that ...</p>