NOTE -- THIS IS NOT MY CONTENT AND IS NOT MEANT TO PLAGERIZE ANY REFERENCED RESOURCES. I HAVE PUT THESE TWO IN A SINGLE PLACE AND REFERECED TO OFFICIAL DOCUMENTATION.
Scroll to "Zoom" section -- https://developers.google.com/maps/documentation/ios-sdk/views
The zoom level of the camera determines the scale of the map. At larger zoom levels more detail can be seen on the screen, while at smaller zoom levels more of the world can be seen on the screen. At zoom level 0, the scale of the map is such that the entire world has a width of approximately 256 points.
Increasing the zoom level by 1 doubles the width of the world on the screen. Hence at zoom level N, the width of the world is approximately 256 * 2N, i.e., at zoom level 2, the whole world is approximately 1024 points wide. Note that the zoom level need not be an integer. The range of zoom levels permitted by the map depends on a number of factors including location, map type and screen size. The following list shows the appr