Problem with timestamps

ROOT
1

Hello,

  1. I have an ascii file with two columns, one for timestamps (in human readable
    local CET/CEST time) and other for values. From that data, I create a ROOT tree,
    by creating an object of the class TDatime, and converting it to an Int_t using
    the Convert method.
TDatime da(myYear,myMonth,myDay,myHour,myMinute,mySecond);
myInt=da.Convert();

When I use the TreeViewer to display the data, I observe a shift of -1 day for
timestamps between March 1st 2007 to February 29th 2008, and for all the 12 months
before any February 29th. How can I solve this?

  1. I then want to plot the data in a postscript file, and for that I use the
    class TH2F.
TH2F *h = new TH2F("h","Values vs time",100,1210240800,1210291200,100,0,130);
//...
h->GetXaxis()->SetTimeDisplay(1);
h->GetXaxis()->SetTimeOffset(0);

What I observe this time is that:
a) the x-axis has a shift of +3 hours with respect to what was requested;
b) all timestamps appear with a shift of +1 hour.
How can I solve this?

Thank you in advance.

Best regards,
Ana Sofia Nunes

File dummy.txt

dummy_name dummy_alias f 35
07 05 2008 09 55 29 1.797300000000e-02 0
08 05 2008 14 25 10 2.754861500000e+01 0
08 05 2008 14 25 30 5.166239000000e+00 0
08 05 2008 14 25 50 2.462700400000e+01 0
08 05 2008 14 26 10 8.617055000000e+00 0
08 05 2008 14 26 30 3.101141300000e+01 0
08 05 2008 14 26 50 4.666989000000e+00 0
08 05 2008 14 27 10 3.494750000000e-01 0
08 05 2008 16 45 30 1.005489500000e+01 0
08 05 2008 16 45 50 2.463898600000e+01 0
08 05 2008 16 46 10 4.730094200000e+01 0
08 05 2008 16 46 30 6.173326100000e+01 0
08 05 2008 16 46 50 7.664885400000e+01 0
08 05 2008 16 47 10 8.213661000000e+01 0
08 05 2008 16 47 30 9.949054000000e+01 0
08 05 2008 16 47 50 1.110911130000e+02 0
08 05 2008 16 48 10 1.152848130000e+02 0
08 05 2008 16 48 50 1.177650870000e+02 0
08 05 2008 16 49 10 9.726388500000e+01 0
08 05 2008 16 49 30 1.139068830000e+02 0
08 05 2008 16 49 50 1.191050740000e+02 0
08 05 2008 16 50 30 9.713607700000e+01 0
08 05 2008 16 50 50 9.545660000000e+01 0
08 05 2008 16 51 10 1.064540790000e+02 0
08 05 2008 16 51 30 1.153587020000e+02 0
08 05 2008 16 52 30 1.112828250000e+02 0
08 05 2008 16 52 50 9.380508100000e+01 0
08 05 2008 16 53 10 7.958644100000e+01 0
08 05 2008 16 53 30 5.610172100000e+01 0
08 05 2008 16 53 50 4.089256900000e+01 0
08 05 2008 16 54 10 1.733795400000e+01 0
08 05 2008 16 54 30 6.578118000000e+00 0
08 05 2008 16 54 50 2.500244000000e+00 0
08 05 2008 16 55 10 4.073880000000e-01 0
13 05 2008 16 47 50 0.000000000000e+00 0

File dummy_convert.c

#include "Riostream.h"
#include "time.h"
                                                                                
void dummy_convert() {
  struct sensor_t {
    Float_t value;
    Int_t myTime;
  };
  sensor_t sensor;
  TString name;	
  TString alias;	
  TString myValue;	
  Char_t type[1];
  int myYear,myMonth,myDay,myHour,myMinute,mySecond,number;
  int invalid;
  int nlines=0;                                                                 
  ifstream fp1;
  fp1.open("dummy.txt");		
  TFile f("dummy.root","recreate");
  while (!fp1.eof()) {
    if (!fp1.good()) {
      cout << "File not ok!" << endl;
      break;
    }
    fp1 >> name >> alias >> type >> number;
    if (alias=="dummy_alias"){
      if (number != 0) {
	TTree *tree1 = new TTree(alias, alias);
	tree1->Branch("value", &sensor.value, "value/F");
	tree1->Branch("time", &sensor.myTime, "myTime/I");
	while (nlines<number) {              
	  fp1 >> myDay >> myMonth >> myYear >> myHour >> myMinute >> mySecond >> myValue >> invalid;	
	  sensor.value = atof(myValue);	    
          TDatime da(myYear, myMonth, myDay, myHour, myMinute, mySecond);
          sensor.myTime = da.Convert();
	  if (invalid == 0) tree1->Fill();
          nlines++; 
	} //nlines
	number = nlines = 0;
	tree1->Print();
	tree1->Write();
      } //if (number != 0)
    else cout << "number = 0" << endl;
    } //alias
    number = nlines = 0;
  } //while(1)
  fp1.close();
}

File dummy_plot.c:

#include "time.h"
                                                                                
void dummy_plot() {
  TFile f("dummy.root");
  TIter nextkey(f.GetListOfKeys());
  TKey *key;
  Int_t time;
  Float_t value;
  Int_t n=1;
  TCanvas *c1 = new TCanvas("c1","Data",800,600);
  c1->Print("MyPlots.ps[");
  TH2F *h = new TH2F("h","Values vs time",100,1210240800,1210291200,100,0,130);
  while ( key = (TKey*)nextkey()) {
    TTree *t = (TTree*)key->ReadObj();
    Int_t nentries = (Int_t)t->GetEntries();
    t->SetBranchAddress("value",&value);
    t->SetBranchAddress("time",&time);	
    char *myTitle = (char*)t->GetName();
    gStyle->SetStatX(0.7);
    h->GetYaxis()->SetLabelSize(0.025);
    h->GetXaxis()->SetLabelSize(0.025);
    h->GetXaxis()->SetTimeDisplay(1);
    h->GetXaxis()->SetTimeOffset(0);
    h->GetXaxis()->SetTitle(myTitle);
    for (Int_t i=0; i<nentries; i++) {
      t->GetEntry(i);
      h->Fill(time,value);
    }
    h->SetOption("COLZ");
    h->Draw();
    c1->Print("MyPlots.ps");
    n++;
    h->Reset();
  }
  c1->Print("MyPlots.ps]");
}
2

have you tried the " gmt" option ?

h->GetXaxis()->SetTimeOffset(0,"gmt");
3

Hello,

Thank you for your answer. By using your suggestion,

h->GetXaxis()->SetTimeOffset(0,"gmt");

the result changes as follows:
2. a) the x-axis has a shift of -1 hour with respect to what was requested;
b) all timestamps appear with a shift of -1 hour.

Ideas? Thank you in advance.

Regards,
Sofia

4

I’ll look at it. I’ll let you know.

5

I tried to run your example but I get a crash. I did:

What should I do exactly to run your code and see the problem ?

6

Can you email me the files I need at Olivier.Couet@cern.ch ?

7

Hi,
I also have suffer the same problem recently. Have you solved this problem? If so,would you please tell me how to solve it?
Thanks in advance.
Best regards
Luo

8

Do you have a small macro reproducing the problem ?

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