{
  TCanvas *c = new TCanvas("c","Graph2D example",0,0,600,400);

  TGraph2D *dt = new TGraph2D("graph.dat");

  gStyle->SetPalette(1);

  Double_t contours[] = {20,40,60,80,100,120,140,160,180,200};

  // Set the canvas range a bit bigger than the x,y data ranges
  c->Range(0,0,160,160); // does not work
  c->SetTheta(-90);
  c->SetPhi(-89.99);
  TH2D* h = new TH2D();
  h = dt->GetHistogram();      // Get histo interpolated between
                               // control points in dt.
  h->SetContour(10,contours);     // Set 10 contour levels (default is 20)
  h->Draw("surf2");            // Draw interpolated points as surface
  h->Draw("cont1 same");       // Contour the surface
  dt->SetMarkerStyle(8);       // Marker for the control points
  dt->Draw("p same");             // Superimpose the control points
  dt->GetZaxis()->SetNdivisions(2);
  //draw text at each point
  Double_t xyz[3], uv[2];
  Int_t np = dt->GetN();
  c->Update();

  TView *view = c->GetView();


   TText t;
   t->SetTextSize(0.035);
   for (Int_t i=0;i<np;i++) {
      xyz[0] = dt->GetX()[i];
      xyz[1] = dt->GetY()[i];
      xyz[2] = dt->GetZ()[i];
      view->WCtoNDC(xyz,uv);
      t->DrawText(uv[0]+0.01,uv[1],Form("point %d",i));
   }
   return c;
}