Re: [ROOT] Reverse lower and upper ranges for TH2D?

From: Olivier Couet (Olivier.Couet@cern.ch)
Date: Thu Apr 15 2004 - 11:17:23 MEST


Hi Mark,

 An other possible way is the attached example.

Cheers,       Olivier


On Thu, 15 Apr 2004, Rene Brun wrote:

> Hi Mark,
> 
> 2-D histograms with axis coordinates increasing from right to left are
> not supported. However, you can visualize a 2-D histogram with the option "surf"
> by setting the viewing angles such that, eg the x axis coordinates will go
> from right to left as shown in the small example below.
> 
> Rene Brun
> 
> {
>   TH2F *hpxpy  = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
>   Float_t px, py;
>   TRandom r;
>   for (Int_t i = 0; i < 25000; i++) {
>      r.Rannor(px,py);
>      hpxpy->Fill(px,py);
>   }
>   TCanvas *c1 = new TCanvas("c1");
>   c1->SetTheta(90.001);
>   c1->SetPhi(90.001);
>   hpxpy->Draw("surf2");
> }
>   
> 
> Mark Polsen wrote:
> > 
> > Hello all,
> > 
> > Is there a way to reverse the lower and upper ranges for a TH2D? I'm
> > using 2D histograms to display astrophysical sources in galactic
> > coordinates. Currently, I can only display the longitude coordinates
> > increasing from left to right. I'd like to display the longitude
> > coordinates increasing from right to left.
> > 
> > Thanks,
> > Mark
> 
> 

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