app/views/access_points/index.kml.erb
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document>
<% @access_points.where("latitude is not null and longitude is not null").each do |access_point| %>
<Placemark id="<%= access_point.id %>" >
<name><%= access_point.name %></name>
<access_point_type><%= access_pointaccess_point_type %></access_point_type>
<%= access_point.geometry.kml_representation.html_safe %>
</Placemark>
<% end %>
</Document>
</kml>