How to draw 2D scattered plot with its projections in same canvas like the attached figure?

dipen · February 27, 2020, 11:56am

Please help me to solve this problem.

Please read tips for efficient and successful posting and posting code

ROOT Version: Not Provided
Platform: Not Provided
Compiler: Not Provided

couet · February 27, 2020, 12:32pm

{
   gStyle->SetFrameFillStyle(0);
   TCanvas *c1 = new TCanvas("c1", "c1",900,900);
   gStyle->SetOptStat(0);

   TPad *h2_pad = new TPad("h2_pad", "h2_pad",0.0,0.0,1.0,1.0);
   h2_pad->Draw();

   proj1_pad = new TPad("proj1_pad", "proj1_pad",0.0,0.0,1.0,1.0);
   proj1_pad->Draw();

   proj2_pad = new TPad("proj2_pad", "proj2_pad",0.0,0.0,1.0,1.0);
   proj2_pad->Draw();

   TH2F *h2 = new TH2F("h2","",40,-4,4,40,-20,20);
   Float_t px, py;
   for (Int_t i = 0; i < 25000; i++) {
      gRandom->Rannor(px,py);
      h2->Fill(px,5*py);
   }
   TH1D * projh2X = h2->ProjectionX();
   TH1D * projh2Y = h2->ProjectionY();

   h2_pad->cd();
   h2->Draw("COL");

   proj2_pad->cd();
   proj2_pad->SetFillStyle(4000);
   projh2X->SetFillColorAlpha(kRed,0.3);
   projh2X->Draw("bar Y+");

   proj1_pad->cd();
   proj1_pad->SetFillStyle(4000);
   projh2Y->SetFillColorAlpha(kGreen,0.3);
   projh2Y->Draw("hbar X+");
}

dipen · February 28, 2020, 8:16am

Thank you very much. I have understood and run your code successfully. But now I am facing another problem. I want to give only the outline in the horizontal histogram without any fill colour like the black histogram of the attached figure.

Thank you in advance.
Please suggest me how to draw it.

couet · February 28, 2020, 9:48am

{
   gStyle->SetFrameFillStyle(0);
   TCanvas *c1 = new TCanvas("c1", "c1",900,900);
   gStyle->SetOptStat(0);

   TPad *h2_pad = new TPad("h2_pad", "h2_pad",0.0,0.0,1.0,1.0);
   h2_pad->Draw();

   proj1_pad = new TPad("proj1_pad", "proj1_pad",0.0,0.0,1.0,1.0);
   proj1_pad->Draw();

   proj2_pad = new TPad("proj2_pad", "proj2_pad",0.0,0.0,1.0,1.0);
   proj2_pad->Draw();

   TH2F *h2 = new TH2F("h2","",40,-4,4,40,-20,20);
   Float_t px, py;
   for (Int_t i = 0; i < 25000; i++) {
      gRandom->Rannor(px,py);
      h2->Fill(px,5*py);
   }
   TH1D * projh2X = h2->ProjectionX();
   TH1D * projh2Y = h2->ProjectionY();

   h2_pad->cd();
   h2->Draw("COL");

   proj2_pad->cd();
   proj2_pad->SetFillStyle(4000);
   projh2X->SetLineColor(kRed);
   projh2X->SetFillStyle(0);
   projh2X->Draw("bar Y+");

   proj1_pad->cd();
   proj1_pad->SetFillStyle(4000);
   projh2Y->SetFillColorAlpha(kGreen,0.3);
   projh2Y->SetFillStyle(0);
   projh2Y->Draw("hbar X+");
}

dipen · February 28, 2020, 11:16am

Thank you.

But I need the y-projection histogram to be drawn only with the boundary line (similar to the x-projection histogram denoted by black solid boundary line

of my attached figure ), not in the form of bar chart.

couet · March 2, 2020, 1:44pm

{
   gStyle->SetFrameFillStyle(0);
   TCanvas *c1 = new TCanvas("c1", "c1",900,900);
   gStyle->SetOptStat(0);

   TPad *h2_pad = new TPad("h2_pad", "h2_pad",0.0,0.0,1.0,1.0);
   h2_pad->Draw();

   proj1_pad = new TPad("proj1_pad", "proj1_pad",0.0,0.0,1.0,1.0);
   proj1_pad->Draw();

   proj2_pad = new TPad("proj2_pad", "proj2_pad",0.0,0.0,1.0,1.0);
   proj2_pad->Draw();

   TH2F *h2 = new TH2F("h2","",40,-4,4,40,-20,20);
   Float_t px, py;
   for (Int_t i = 0; i < 25000; i++) {
      gRandom->Rannor(px,py);
      h2->Fill(px,5*py);
   }
   TH1D * projh2X = h2->ProjectionX();
   TH1D * projh2Y = h2->ProjectionY();

   h2_pad->cd();
   h2->Draw("COL");

   proj2_pad->cd();
   proj2_pad->SetFillStyle(4000);
   projh2X->SetLineColor(kRed);
   projh2X->SetFillStyle(0);
   projh2X->SetLineWidth(3);
   projh2X->Draw("HIST Y+");
   
   proj1_pad->cd();
   proj1_pad->SetFillStyle(4000);
   projh2Y->SetFillColorAlpha(kGreen,0.3);
   projh2Y->SetLineWidth(0);
   projh2Y->SetFillStyle(0);
   auto g = new TGraph();
   int n = projh2Y->GetNbinsX();
   for (int i=0; i<n; i++) {
      g->SetPoint(i+1, projh2Y->GetBinContent(i), projh2Y->GetBinCenter(i) );
   }
   projh2Y->Draw("hbar X+");
   g->SetLineWidth(3);
   g->Draw("L");

}

dipen · March 6, 2020, 4:02pm

This is the plot which I got from your last updated code. But I want to show the the y-component histogram only by outlines(similar to x-component histogram).

couet · March 6, 2020, 4:10pm

Ok this is more tricky I need time.

dipen · March 6, 2020, 5:00pm

Thank you Sir,

"I will be waiting for your help "

couet · March 6, 2020, 5:01pm

{
	gStyle->SetFrameFillStyle(0);
	TCanvas *c1 = new TCanvas("c1", "c1",900,900);
	gStyle->SetOptStat(0);

	TPad *h2_pad = new TPad("h2_pad", "h2_pad",0.0,0.0,1.0,1.0);
	h2_pad->Draw();

	proj1_pad = new TPad("proj1_pad", "proj1_pad",0.0,0.0,1.0,1.0);
	proj1_pad->Draw();

	proj2_pad = new TPad("proj2_pad", "proj2_pad",0.0,0.0,1.0,1.0);
	proj2_pad->Draw();

	TH2F *h2 = new TH2F("h2","",40,-4,4,40,-20,20);
	Float_t px, py;
	for (Int_t i = 0; i < 25000; i++) {
		gRandom->Rannor(px,py);
		h2->Fill(px,5*py);
	}
	TH1D * projh2X = h2->ProjectionX();
	TH1D * projh2Y = h2->ProjectionY();

	h2_pad->cd();
	h2->Draw("COL");

	proj2_pad->cd();
	proj2_pad->SetFillStyle(4000);
	projh2X->SetLineColor(kRed);
	projh2X->SetFillStyle(0);
	projh2X->SetLineWidth(5);
	projh2X->Draw("HIST Y+");

	proj1_pad->cd();
	proj1_pad->SetFillStyle(4000);
	projh2Y->SetLineWidth(0);
	projh2Y->SetFillStyle(0);
	auto g = new TGraph();
	int n = projh2Y->GetNbinsX();
	double x, y;
	double bw = projh2Y->GetBinWidth(1);
	int i = 0;
	y = projh2Y->GetBinLowEdge(1);
	g->SetPoint(i, 0, y); 
	for (int b=1; b<=n; b++) {
        x = projh2Y->GetBinContent(b);
		y = projh2Y->GetBinLowEdge(b);
		g->SetPoint(i, x, y); i++;
		g->SetPoint(i, x, y+bw); i++;
	}
	projh2Y->Draw("hbar X+");
	g->SetLineColor(kYellow);
	g->SetLineWidth(5);
	g->Draw("L");
}

dipen · March 7, 2020, 6:47am

Dear Sir,

The plot you have attached is exactly what I want. I need that. Thank you.
But, the code you sent is not giving me that plot. I have run your code and found the following plot ( same as before, attached here).

What should I add in the code to get exactly your plot ?

Thank you,
Dipen

couet · March 9, 2020, 8:45am

Can you use a more recent version of ROOT ? the macro I sent you relies on the fact a line width of 0 allow to not draw the line.

dipen · March 9, 2020, 1:53pm

Thank you for your reply… ok I am checking it.

sanchari · March 10, 2020, 10:14am

Hi couet,

I am a PhD student in experimental high energy physics in ALICE. I also need this plot . I am also not getting this plot by running the code given here.

As suggested, I also tried with a latest version of ROOT in Aliroot framework (lxplus) vAN-20200308_ROOT6-1 and also the same version in root 5, but it did not work. I am still getting the horizontal lines.

Thanks,
Sanchari

sanchari · March 10, 2020, 4:41pm

I checked the aliroot version. It was written ROOT 6-2 in that aliroot version.

dipen · March 10, 2020, 4:51pm

I am getting the horizontal lines in the y-projection histogram by usjing ROOT 6.12.04. Can you please tell me what version root is used to get the actual histogram.

couet · March 10, 2020, 5:24pm

According to git history it was implemented in 2015 in ROOT 6.04

Wile_E_Coyote · March 10, 2020, 5:30pm

For me it does not work with 6.16/00 nor with 6.14/06. First 6.18/04, 6.19/02 and 6.20/00 work fine.

couet · March 10, 2020, 5:35pm

Ok, instead of discussing which ROOT version has it or not, I made a new version of the macro which does not depend on the line width = 0:

{
	gStyle->SetFrameFillStyle(0);
	TCanvas *c1 = new TCanvas("c1", "c1",900,900);
	gStyle->SetOptStat(0);

	TPad *h2_pad = new TPad("h2_pad", "h2_pad",0.0,0.0,1.0,1.0);
	h2_pad->Draw();

	proj1_pad = new TPad("proj1_pad", "proj1_pad",0.0,0.0,1.0,1.0);
	proj1_pad->Draw();

	proj2_pad = new TPad("proj2_pad", "proj2_pad",0.0,0.0,1.0,1.0);
	proj2_pad->Draw();

	TH2F *h2 = new TH2F("h2","",40,-4,4,40,-20,20);
	Float_t px, py;
	for (Int_t i = 0; i < 25000; i++) {
		gRandom->Rannor(px,py);
		h2->Fill(px,5*py);
	}
	TH1D * projh2X = h2->ProjectionX();
	TH1D * projh2Y = h2->ProjectionY();

	h2_pad->cd();
	h2->Draw("COL");

	proj2_pad->cd();
	proj2_pad->SetFillStyle(4000);
	projh2X->SetLineColor(kRed);
	projh2X->SetFillStyle(0);
	projh2X->SetLineWidth(5);
	projh2X->Draw("HIST Y+");

	proj1_pad->cd();
   TH1D *f = new TH1D("f","f",100,projh2Y->GetXaxis()->GetXmin()
		                           ,projh2Y->GetXaxis()->GetXmax());
	f->SetMaximum(projh2Y->GetMaximum());
	f->SetMinimum(projh2Y->GetMinimum());
	proj1_pad->SetFillStyle(4000);

	projh2Y->SetFillStyle(0);
	auto g = new TGraph();
	int n = projh2Y->GetNbinsX();
	double x, y;
	double bw = projh2Y->GetBinWidth(1);
	int i = 0;
	y = projh2Y->GetBinLowEdge(1);
	g->SetPoint(i, 0, y);
	for (int b=1; b<=n; b++) {
        x = projh2Y->GetBinContent(b);
		y = projh2Y->GetBinLowEdge(b);
		g->SetPoint(i, x, y); i++;
		g->SetPoint(i, x, y+bw); i++;
	}
	f->Draw("hbar X+");
	g->SetLineColor(kYellow);
	g->SetLineWidth(5);
	g->Draw("L");
}

dipen · March 11, 2020, 12:08pm

Dear Couet,
Thank you very much. Your code is working. I got the appropriate plot.