Horizontal line through zero bin content

Newbie
1

Hi Everyone,

I am trying to plot two 1D histograms on the
same canvas with non-zero bin contents from 0 to 0.7. However, the histograms produced also draw a line over zero bin contents. Is it possible to get rid of this line?

histogram_0line
histogram_0line698Ă—476 2.91 KB

I went through the old post by @couet answering a similar question however the SetMinmum(0) option seems to have no effect. Can someone please help me determine where I am making a mistake or how to remove this line?

Thanks a lot for your time and consideration!

Edit1: I think the SetMinium(0) histogram seems to work. However, there is an issue when I plot another histogram on the same canvas

h8->SetMinimum(0)
h8->Draw()

h8
h8698Ă—476 2.85 KB

h9->SetMinimum(0)
h9->Draw()

h9
h9698Ă—476 3.95 KB

h8->Draw("same")

h8_plus_h9
h8_plus_h9698Ă—476 2.93 KB

2

What I see on your plot is not “a line at 0” but the bins after the high peaks having 0 as content. That’s the “red line” overwriting the axis . You need to redraw the axis with:

gPad->RedrawAxis();
1 Like
3

Thanks a lot for your prompt reply and accurate solution !

By the way, is the Redraw() axis option something we shall do always while plotting multiple graphs ?

4

It depends what users want. Sometimes one want to see the bin drawn even if it is on the axis. That’s why we cannot make it automatic by default…

5

Yes, that’s quite reasonable