http://brainafk.com/29159264

gistfile1.cs

var statusChangedToReady = from sc in statusChanged
                           where sc.Status == GeoPositionStatus.Ready
                           select sc;

var positionChanged = from _ in statusChangedToReady
                      from pc in watcher.GetPositionChangedEventObservable()
                      where !pc.EventArgs.Position.Location.IsUnknown
                      select pc.EventArgs.Position;