Time for Action – determining LonLat coordinates

Let's take a look at a couple of examples on coordinates from our previous maps.

1. Open up the final example from Chapter 1.

2. Pan around the map in any direction. Then, in Firebug, type:

   map.getCenter();

3. Depending on where you have panned, your output should read something like this:

   lon=-72.8125, lat=19.6875
   

4. Now, open up the example from the beginning of this chapter.

5. Pan around, and then in Firebug type:

   map.getCenter();

6. You should see something like:

   lon=-9397474.0038099,lat=3595597.9798909
   

What Just Happened?

We just took a look at the longitude and latitude values for the center of the map in two different maps with different projections. When we call map.getCenter(), we get back an OpenLayers LonLat object.

In the first map, the max extent of the map was between -180° and 180° for longitude, and between -90° and 90° for latitude. These are the values used by the EPSG: 4326, and it is a longitude/latitude type of coordinate system. The values for...