void pl_resi2D_trk(Int_t NSt=8, Int_t iVar=0, Int_t iFit=0){
  //  TCanvas *can = new TCanvas("can22","can22");
  //  can->Divide(2,2); 
  TCanvas *can = new TCanvas("can","can",50,0,800,800);
  switch(NSt){
  case 6:
  case 5:
  case 4:
    can->Divide(3,3);
    break;
  case 7:
  case 8:
        can->Divide(3,4);
    break;
  case 16:
  case 18:
    can->Divide(4,5);
    break; 
  case 30:
    can->Divide(6,6);
    break;
  case 39:
    can->Divide(6,7);
    break;
  default:
    can->Divide(5,5);
    ; 
  }
 gPad->SetFillColor(0);
 gStyle->SetPalette(1);
 gStyle->SetOptStat(kTRUE);

 gROOT->cd();
 gROOT->SetDirLevel(1);

 TH1 *h;
 TH1 *h1;
 TH2 *h2;

 const Int_t MSt=30;
 Double_t vSt[MSt];
 Double_t vMean[MSt];
 Double_t vSig[MSt];
 Double_t vRes[MSt];
 Double_t vStErr[MSt];
 Double_t vMeanErr[MSt];
 Double_t vSigErr[MSt];
 Double_t vResErr[MSt];
 // if (h!=NULL) h->Delete();
 Int_t iCan=1;
 TString var;
 Double_t Nall;

 switch(iVar){
 case 0:
   var="ResidualTBWalk";
   break;
 case 1:
   var="ResidualYWalk";
   break;
 }

 for (Int_t iSt=0; iSt<NSt; iSt++) {
   if (iCan==36) iCan=1;
 can->cd(iCan++);
 gROOT->cd();
 TString hname=Form("h%s_Station_%d",var.Data(),iSt);
  h2=(TH2 *)gROOT->FindObjectAny(hname);
  if (h2!=NULL) {
      h2->Draw("colz");
      gPad->SetLogz();
      gPad->SetGridx();
      gPad->SetGridy();
  }else 
   {
     cout << hname << " not found" << endl;
   }
 }
 
 can->SaveAs(Form("pl_trk_%s_%02d.pdf",var.Data(),NSt));
}