markerwarning.C: This script illustrates the danger of using asymmetric symbols.

// This script illustrates the danger of using asymmetric symbols.
// Non-symmetric symbols should be used carefully in plotting.
// These two graphs show how misleading a careless use of symbols can be.
// The two plots represent the same data sets but because of a bad symbol 
// choice, the two plots on the top appear further apart than for the bottom 
// example.
//Author: Olivier Couet
   
void markerwarning()
{
   const int Nph = 14;
   double np_ph[Nph]  = {353.4,300.2,254.3,215.2,181.0,151.3,125.2,102.7, 
      83.3, 66.7, 52.5, 40.2, 30.2, 22.0};
   double nc_ph[Nph]  = {3.890,3.734,3.592,3.453,3.342,3.247,3.151,3.047,
      2.965,2.858,2.701,2.599,2.486,2.328};
   double npe_ph[Nph] = {10.068,9.004,8.086,7.304,6.620,6.026,5.504,5.054,
      4.666,4.334,4.050,3.804,3.604,3.440};
   double nce_ph[Nph] = {0.235,0.217,0.210,0.206,0.213,0.223,0.239,0.260,
      0.283,0.318,0.356,0.405,0.465,0.545};

   const int Nbr = 6;
   double np_br[Nbr]  = {357.0,306.0,239.0,168.0,114.0, 73.0};
   double nc_br[Nbr]  = {3.501,3.275,3.155,3.060,3.053,3.014};
   double npe_br[Nbr] = {8.000,11.000,10.000,9.000,9.000,8.000};
   double nce_br[Nbr] = {0.318,0.311,0.306,0.319,0.370,0.429};

   TGraphErrors *phUP = new TGraphErrors(Nph,np_ph,nc_ph,npe_ph,nce_ph);
   TGraphErrors *phDN = new TGraphErrors(Nph,np_ph,nc_ph,npe_ph,nce_ph);
   TGraphErrors *brUP = new TGraphErrors(Nbr,np_br,nc_br,npe_br,nce_br);
   TGraphErrors *brDN = new TGraphErrors(Nbr,np_br,nc_br,npe_br,nce_br);

   float Top_margin   = 0.;
   float Left_margin  = 0.025;
   float Right_margin = 0.005;
   float maxPlotPart  = 395;
   float Marker_Size  = 1.3;
   int   Marker_Style = 8;
  
   float Et_200_Min   = 0.71;
   float Et_200_Max   = 3.80;
   float Et_130_Min   = 1.21;
   float Et_130_Max   = 3.29;
  
   float Nc_200_Min   = 1.31;
   float Nc_200_Max   = 4.30;
   float Nc_130_Min   = 1.51;
   float Nc_130_Max   = 3.89;
  
   TCanvas *canvasNc = new TCanvas("canvasNc", "Multiplicity",630,10,600,500);
  
   gStyle->SetOptStat(0);
   canvasNc->SetFillColor(10);
   canvasNc->SetBorderSize(0);
  
   // Primitives in Nc200 pad
   TPad *padNcUP = new TPad("padNcUP","200 GeV",0.07,0.60,1.,1.00);
   padNcUP->Draw();
   padNcUP->cd();
   padNcUP->SetFillColor(10);
   padNcUP->SetFrameFillColor(10);
   padNcUP->SetBorderSize(0);
   padNcUP->SetLeftMargin(Left_margin);
   padNcUP->SetRightMargin(Right_margin);
   padNcUP->SetTopMargin(Top_margin+0.005);
   padNcUP->SetBottomMargin(0.00);
  
   TH1F* frameNcUP = new TH1F("frameNcUP","",100,0,maxPlotPart);
   frameNcUP->GetYaxis()->SetLabelOffset(0.005);
   frameNcUP->GetYaxis()->SetLabelSize(0.10);
   frameNcUP->SetMinimum(Nc_200_Min);
   frameNcUP->SetMaximum(Nc_200_Max);
   frameNcUP->SetNdivisions(505,"Y");
   frameNcUP->SetNdivisions(505,"X");
   frameNcUP->Draw();
  
   brUP->SetMarkerStyle(22);
   brUP->SetMarkerSize (2.0);
   brUP->Draw("P");                    
  
   phDN->SetMarkerStyle(23);
   phDN->SetMarkerSize (2);
   phDN->Draw("P");
  
   canvasNc->cd();
  
   // Primitives in Nc130 pad
   TPad *padNcDN = new TPad("padNcDN","130 GeV",0.07,0.02,1.,0.60);
   padNcDN->Draw();
   padNcDN->cd();
   padNcDN->SetFillColor(10);
   padNcDN->SetFrameFillColor(10);
   padNcDN->SetBorderSize(0);
   padNcDN->SetLeftMargin(Left_margin);
   padNcDN->SetRightMargin(Right_margin);
   padNcDN->SetTopMargin(Top_margin+0.005);
   padNcDN->SetBottomMargin(0.30);
  
   TH1F* frameNcDN = new TH1F("frameNcDN","",100,0,maxPlotPart);
   frameNcDN->GetYaxis()->SetLabelOffset(0.005);
   frameNcDN->GetYaxis()->SetLabelSize(0.07);
   frameNcDN->GetXaxis()->SetLabelOffset(0.005);
   frameNcDN->GetXaxis()->SetLabelSize(0.07);
   frameNcDN->SetMinimum(Nc_200_Min);
   frameNcDN->SetMaximum(Nc_200_Max);
   frameNcDN->SetNdivisions(505,"Y");
   frameNcDN->SetNdivisions(505,"X");
   frameNcDN->Draw();
  
   brDN->SetMarkerStyle(23);
   brDN->SetMarkerSize (2.0);
   brDN->Draw("P");                    
             
   phUP->SetMarkerStyle(22);
   phUP->SetMarkerSize (2);
   phUP->Draw("P");

   TLatex t1;
   t1.SetTextFont(12); t1.SetTextSize(0.0525);
   t1.DrawLatex(-5,0.6,"Non-symmetric symbols should be used carefully in plotting. \
      These two graphs show how misleading");
   t1.DrawLatex(-5,0.4,"a careless use of symbols can be. The two plots represent \
      the same data sets but because of a bad");
   t1.DrawLatex(-5,0.2,"symbol choice, the two plots on the top appear further apart \
      than for the bottom example.");

   canvasNc->cd();
}