void tb_PreviewTouchDown(object sender, TouchEventArgs e)
{
TextBlock dot = (TextBlock)sender;
naturenet_dataclassDataContext db = new naturenet_dataclassDataContext();
var loc = from l in db.Locations
where l.id == (int)dot.Tag
select l;
Location location = loc.Single<Location>();
log.WriteInteractionLog(11, "Location: " + location.id.ToString(), e.TouchDevice);
window_manager.open_location_collection_window(location.name, location.id, Canvas.GetLeft(dot), Canvas.GetTop(dot));
}