Superimposing a scatter plot

Scott Sampson (scott@znev03.desy.de)
Mon, 12 Oct 1998 20:53:18 +0100 (MET)


Hi,

I want to do something which seems relatively simple, but I can't get it
to work:

I have a TGraphErrors object in one file, and a TTree object in another
file. I want to superimpose a scatter plot from the Tree onto the Graph. I
want to do this for a specified axis range and use log scales in x and y.
So I use the macro below. The problem is that I get the points from the
graph, but no scatter plot. It seems that ROOT doesn't like my attempt to
superimpose a scatter plot on a pre-existing frame. (i.e. I first use a
gPad->DrawFrame(. . .) then an h14->Draw("y:x", "SAME") )
Is there a fix for this? Thanks,

Scott Sampson
Columbia University

Int_t plt() {

c1->Clear();

TFile *g = new TFile("lepto/nc_cc_xsec2.root");
TTree *h14 = (TTree*)g->Get("h14") ;

TFile *f = new TFile("root/graphs.root");
TGraphErrors *tgr = (TGraphErrors *)f->Get("grx");

MakePad(1,2,1,1);
gPad->SetLogx();
gPad->SetLogy();
gPad->DrawFrame(0.01,0.01,1.0,1000);

tgr->Draw("P");
h14->Draw("sig/(xh-xl):xc","flg==0","SAME");

gPad->Update();

}