Demonstrates populating a PointTrack layer with gx:Track elements from KML.
If a KML document contains <gx:Track>
elements and the extractTracks property is set true on the
parser, features will be created that represent track points.
These track points can easily be visualized as track lines with
a PointTrack layer, preserving the KML's original
styles.
View the kml-pointtrack.js source to see how this is done.