Time for Action – setting zoom levels and maxExtent

1. Create your map object, by specifying the numZoomLevels and adding a PanZoomBar control. We'll also set the numZoomLevels property to 8, meaning that only eight zoom levels will be available. Lastly, we'll set the maxExtent property to include just a subset of the world, like the following:

   map = new OpenLayers.Map('map_element', {
     controls: [
       new OpenLayers.Control.Navigation(),
       new OpenLayers.Control.PanZoomBar(),
       new OpenLayers.Control.LayerSwitcher()
     ],
     numZoomLevels: 8,
     maxExtent: new OpenLayers.Bounds(-100, -30, 40, 30)
   });

2. Open up the page, and you should see something like this:

   

What Just Happened?

Our map has only eight zoom levels and a maximum extent of (-100, -30, 40, 30). You must have noticed that the map started at a zoom level that is zoomed in a couple of times. This is mainly due to the fact that the furthest out zoom level would show more than the maximum extent of the map. Let's quickly talk about...