Multigraph with a linear & a log axis (data set)

[GeetJ]

Hi,
I have the following data sets:
(a) linear X-axis + linear Y1-axis with asymmetric errors
(b) linear X-axis + logarithmic Y2-axis with symmetric errors.
How do I have them on the same plot together? Use multigraph?

[couet]

Welcome to the ROOT forum.

@GeetJ

Use multigraph?

Yes. A TMultiGraph.

[GeetJ]

Thanks couet for replying.
I am unable to have a linear Y1 axis (left) for linear data points and a logarithmic Y2 axis (right) for logarithmic data points. Since my data points have asymmetrical errors on them, I don’t want to scale my data points.

[Wile_E_Coyote]

Draw two graphs on one canvas with different Y scales

Hello. I have two data files and macro. And I need to draw two graphs on one canvas with different Y scales. I have read specific topic in ROOT manual, but unfortunately it hasn’t helped me. Can you help me please to solve this problem. Thank you. comp.C (1006 Bytes)

[GeetJ]

I worked it out by using the transparent pad method:

How to plot with a linear and log scale on two different axes on same plot?

I am trying to figure out how to plot something on a linear axis and then plot another quantity on a log axis on the same plot and then have the two y-axes be on different scales as well. I’m currently attempting to do this with drawing the first histogram on a TPad and then drawing the second histogram on a transparent TPad above it. However, I am not sure how to get a log scale for the second histogram (the log scale is a property of the TCanvas I think, not a TPad) and then how to use TGaxis …

However, there are 2 X-axes that are created since the 1st dataset is in X-range of [0,50] and 2nd dataset is in [20,30]. How to plot the 2nd dataset on the X-axis of the 1st dataset?

[Wile_E_Coyote]

Problem in setting the range of the plot

Actually, for “graphs”, it is very easy to use any “arbitrary values” for the x-axis range: graph->GetHistogram()->GetXaxis()->SetLimits(xmin, xmax);