Thank you. This is exactly what I want. I really appreciate.
Unfortunately, it looks intimidating to me. I do not think, I would be able to come up with that. After seeing bar_spacing setting in your solution, I finally realized its place and by searching, I found where it is embedded. color=isodd.(axes(df,1)) is a brilliant solution which I would have difficulty to come by with my inadequate julia experience.
I have another question about plotting trajectory from datastream via gadfly at my question. I apprecite if you care to comment on that.
Again thank you very much.