Google maps - mouseover elevation along a path

[Al Black]

I'm trying to accomplish this end result http://gmaps-samples-v3.googlecode.com/svn/trunk/elevation/elevation-profile.html with a key difference, the rendered path is along a KML file.

It allows someone to mouse over the elevation graph and the marker moves on the map along the path. You can do this with your own KML file (upload it) at http://www.geocontext.org/publ/2010/04/profiler/en/?import=kml.

I've searched high and low for a tutorial but can't seem to find one - does anyone know of a tutorial to get me started on this perchance?