Plotting events while sweeping across Plane instead of events in X and Y separately

Newbie
1

Hello Experts,

I’m not sure if this is possible/simple, but I’ll ask anyway.

I have two 1D histograms, one that is events in X, and one that is events in Y.

Normally, I create 2D plots that are X vs Y, creating simple histograms using the following snippet of code:

ch.Draw(“Y:X>>h1(500,-10,10,500,-10,10)”,"(X>10&&X<10)&&(Y>-10&&Y<10))",“COL4Z”);

SO this works fine as intended. But what I want to try and do though, is create a 1D plot of events in the XY plane. So as I sweep from left to right on the XY plane, I can figure out how many specific events were there. And then I want to be able to choose the angle I sweep across. Say, maybe I want to sweep top to bottom, or sweep from a 45 degree angle from corner to corner.

I am not sure how to do this, and would be grateful if someone could point me in the right direction if it’s possible?

Thank you very much.

2

As long as you stick to “top-bottom” and / or “left-right”, you can easily apply to your “h1” histogram: TH2::ProfileX, TH2::ProfileY, TH2::ProjectionX, TH2::ProjectionY

For the “45 degree angle”, you would need to draw the “distance from a point to a line”:

ch.Draw("X * TMath::Sin(TMath::DegToRad() * 45.) - Y * TMath::Cos(TMath::DegToRad() * 45.)");
1 Like
3

Great. Thank’s for the insight! This is helpful.