Make cuts on tree without changing the displayed axes

[Paleo]

Hi,

I project a TTree onto a histogram, and apply cuts to them. If I use a specific cut, the displayed histogram axes limits change too, which is not what I want. I would only like the data points that are displayed to change based on the cuts I apply.

I’ve tried to use SetLimits() and SetRange() but that doesn’t force the axes to remain independent of the cuts.

Any help?

[couet]

Do you have a small reproducer ? You create the histogram before projecting ? can you show the commands you are using ?

[Paleo]

Hi,
These are .root files that are required to run smallReproducible.C

You may notice that the longitude axis is not starting from -180ish to 180ish. This causes the map of the Earth to be mirrored.
The archerTree object and its data points are included as it may have a bearing on the graph that is plotted.

ArcherTree.root (170.2 KB)
ElevationB.root (447.6 KB)
smallReproducible.C (1.7 KB)

[couet]

Thanks for you example.
First replace SURF5 by SURF3 to avoid the warnings.

In your code I see:

   archerTree->Project( "h", "(-1*BathDepth):(longit):latit" );

And before you have:

   //Cuts that I would like to use but produce desired axes limits
   TCut cutDepth2030 = "(CaCO3 != -999 && BathDepth > 2000 && BathDepth < 3000)*(abs(CaCO3))";
   TCut cutInd = "longit >= 30 && longit <120 && latit >= -55 && latit < 15";

You are not using the cuts in the project command. Why ?

[Paleo]

I think there is a line of code that I have commented out which uses that. I just commented that out initially to show the difference between using a cut and without it.

[couet]

May be the following will help:

void smallReproducible()
{
   TFile* rootFile = TFile::Open("ElevationB.root");
   TFile* treeFile = TFile::Open("ArcherTree.root");

   TGraph2D* BSeaLevel = new TGraph2D(360*720); //2D array with N rows and M cols
   rootFile->GetObject("Bathymetry_overlay", BSeaLevel);

   TTree* archerTree = new TTree("archerTree", "archerTree"); // Tree with branches such as "CaCO3" and "BathDepth", and are used in TCut
   treeFile->GetObject("ARCHERTREE", archerTree);

   //Cuts that I would like to use but produce desired axes limits
   TCut cutDepth2030 = "(CaCO3 != -999 && BathDepth > 2000 && BathDepth < 3000)*(abs(CaCO3))";
   TCut cutInd = "longit >= 30 && longit <120 && latit >= -55 && latit < 15";

   TCanvas* c2 = new TCanvas( "c2", "Elevation Overlay", 1500, 500 );
   c2->Divide(3,1);

   TH3F* h = new TH3F( "h", "BathDepth vs longitude vs latitude", 100, 0., -1., 100, 0., -1., 100, 0., -1. );
   archerTree->Project( "h", "(-1*BathDepth):longit:latit", cutDepth2030 && cutInd );

   c2->cd(1); h->Draw("BOX");
   gPad->Update();

   BSeaLevel->SetMaximum(h->GetZaxis()->GetXmax());
   BSeaLevel->SetMinimum(h->GetZaxis()->GetXmin());
   BSeaLevel->GetXaxis()->SetRangeUser(h->GetXaxis()->GetXmin(), h->GetXaxis()->GetXmax());
   BSeaLevel->GetYaxis()->SetRangeUser(h->GetYaxis()->GetXmin(), h->GetYaxis()->GetXmax());
   c2->cd(2); BSeaLevel->Draw("SURF3");

   c2->cd(3); BSeaLevel->Draw("SURF3"); h->Draw("BOX SAME");
}

[Paleo]

Does this fix make the TGraph2D change size according to the cuts made on the TTree?

[couet]

@Paleo

Does this fix make the TGraph2D change size according to the cuts made on the TTree ?

Yes because the TGraph2D limits are defined from the histogram limits (see the code).

[Wile_E_Coyote]

@couet In your example, you twice execute “new” and then “GetObject”. It seems to me that they result in memory leaks.

[couet]

@Wile_E_Coyote

In your example

To be honest I did not look at the beginning of the macro… I concentrated on the graphics part. I will check .

[couet]

void smallReproducible()
{
   TFile* rootFile = TFile::Open("ElevationB.root");
   TFile* treeFile = TFile::Open("ArcherTree.root");

   TGraph2D *BSeaLevel = (TGraph2D*)rootFile->Get("Bathymetry_overlay");
   TTree *archerTree = (TTree*)treeFile->Get("ARCHERTREE");

   //Cuts that I would like to use but produce desired axes limits
   TCut cutDepth2030 = "(CaCO3 != -999 && BathDepth > 2000 && BathDepth < 3000)*(abs(CaCO3))";
   TCut cutInd = "longit >= 30 && longit <120 && latit >= -55 && latit < 15";

   TCanvas* c2 = new TCanvas( "c2", "Elevation Overlay", 1500, 500 );
   c2->Divide(3,1);

   TH3F* h = new TH3F( "h", "BathDepth vs longitude vs latitude", 100, 0., -1., 100, 0., -1., 100, 0., -1. );
   archerTree->Project( "h", "(-1*BathDepth):longit:latit", cutDepth2030 && cutInd );

   c2->cd(1); h->Draw("BOX");
   gPad->Update();

   BSeaLevel->SetMaximum(h->GetZaxis()->GetXmax());
   BSeaLevel->SetMinimum(h->GetZaxis()->GetXmin());
   BSeaLevel->GetXaxis()->SetRangeUser(h->GetXaxis()->GetXmin(), h->GetXaxis()->GetXmax());
   BSeaLevel->GetYaxis()->SetRangeUser(h->GetYaxis()->GetXmin(), h->GetYaxis()->GetXmax());
   c2->cd(2); BSeaLevel->Draw("SURF3");

   c2->cd(3); BSeaLevel->Draw("SURF3"); h->Draw("BOX SAME");
}

[Wile_E_Coyote]

Using “Get” should be prohibited by law.

   TGraph2D *BSeaLevel; rootFile->GetObject("Bathymetry_overlay", BSeaLevel);
   TTree *archerTree; treeFile->GetObject("ARCHERTREE", archerTree);