void gr110_logscale() { auto c = new TCanvas("c","Reversed graphs",0,0,900,400); c->Divide(2,1); c->cd(1); const Int_t n = 6; //Fill the arrays x and y with the data points Double_t x[n], y[n]; for (Int_t i=0;iSetLineColor(2); gr1->SetLineWidth(4); gr1->SetMarkerColor(4); gr1->SetMarkerStyle(21); gr1->SetTitle("Graph without log scale"); gr1->DrawClone("ACP"); //The logarithmic scale setting can also be done in a ROOT interactive session. c->cd(2); gPad->SetLogy(); //gPad->SetLogx(); Uncomment this line if log scale is needed on both axes gr1->SetTitle("Graph with y log scale"); gr1->Draw("ACP"); }