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Confidence Levels in Root


I am changing the range…then also it is not coming as in gnuplot : Range for test1.dat :
TH2F *hcont2 = new TH2F(“hcont2”," ",40,0,360,40,0,0.9);


Well … it is hard to make a contour plot with a such histogram:


ohhkk… Now, I am trying a graph plot…
By fixing z axis value… a graph between x and y axes.
This is not working… Please see my updated folder
datafiles.tar.gz (1.5 KB)

Thank you.


well a TGraph will simply connect the point (in order). I get the following picture using the option “al*”


Yes, exactly I am also getting this. But if we use gnuplot with the script that I have updated in the folder it gives a different picture, I want to use ROOT for plotting this… Contours plots from ROOT.


But look at the points you gave to TGraph … they are aligned on columns … nothing like a contour. As I said TGraph simply link the points by a line. if you want a contour your points should define it properly. I am curious to see the gnuplot script you are using with this data file and the kind of plot you get.


I tried your commands in gnuplot. But it does not work for me.

gnuplot> set contour
gnuplot> set view map
gnuplot> unset surface
gnuplot> set cntrparam discrete levels 2.3,6.2,11.8
         expecting 'linear', 'cubicspline', 'bspline', 'points', 'levels' or 'order'

gnuplot> splot "test1.dat" with lines
WARNING: Plotting with an 'unknown' terminal.
No output will be generated. Please select a terminal with 'set terminal'.

  TGraph2D *g1 = new TGraph2D("test1.dat");
  g1->SetNameTitle("g1", "test1;x;y;z");
  TGraph2D *g2 = new TGraph2D("test2.dat");
  g2->SetNameTitle("g2", "test2;x;y;z");
  Double_t c3[3] = {2.3, 6.2, 11.8};
  TCanvas *c = new TCanvas("c", "c", 800, 400);
  c->Divide(2, 1);
  g1->Draw("SURF3"); // e.g. "SURF3" or "CONT5"
  g1->GetHistogram()->SetContour(3, c3);
  g2->Draw("SURF3"); // e.g. "SURF3" or "CONT5"
  g2->GetHistogram()->SetContour(3, c3);


Yes or


which gives:

But i am not sure that’s what @srishino wants as he tried tor Draw the contour directly for the dat file … that might suggest that the data in the dat file are defining the contour.


This is the plot that I am getting using the script below-
gnuplot> set contour
gnuplot> set view map
gnuplot> unset surface
gnuplot>set cntrparam levels discrete 2.3,6.2,11.8
gnuplot> splot [0:360][0:0.9] “test1.dat” with lines

mygnuplot.pdf (7.7 KB)


These are the details of GNUPLOT version that I am using-

Version 4.6 patchlevel 2    last modified 2013-03-14 
Build System: Linux x86_64


gnuplot> set terminal pdf


have you tried Wile suggestion ?


I just tried this… I am getting the plot attached below-

myRootplot.pdf (117.1 KB)

I want only the red portion as a one-dimensional plot…


Instead of “SURF3”, try “CONT5”, …, “CONT0”.


Yea its working… Thanks a lot… :slight_smile: