Yes, it helps. But it makes the graph not very clear, because that means that a large window with only a few lines makes it look like everything is clustered funny. For instance, if there are only ten lines of actual track data, but the window is 50 lines tall, it looks like the tracks are horribly clustered when they really aren't.

Maybe the graph should be a fixed height depending on the number of lines, and let the user change the graph's width by changing the window size. If the graph is too big to fit in the window, put a scroll bar or something.