Do you remember what happens when you click on the OpenLayers link from the Layer Preview page? A small web application opens, and it shows you a map with the data contained in the layer you selected. It is an application based on the OpenLayers framework, and this is also a specific format of output for your layers.
OpenLayers is an open source JavaScript library to display web-based maps, similar to the mapping client from Google Maps and a growing number of others. OpenLayers is also a project of the Open Source Geospatial Foundation (OSGeo). LeafLet (http://leafletjs.com) is a promising mapping client with ties to OpenLayers. Be on the lookout for examples using LeafLet in future chapters.
