Draw the section of a TH2 taken at the desired position

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Hi @Ziel_van_brand,
and sorry for the late reply!

for each bin along x, it seems it makes and plots the integral along y at that x.

Indeed a histogram projection integrates the bin contents along one axis, see e.g. this thread. You can use the firstybin and lastybin arguments to only consider a slice of the Y axis when performing the projection (see the docs).

So to get a slice along x at a given constant y you need to set firstybin and lastybin to the bin number corresponding to that y value:

// haven't tested the code but it should give you an idea
const auto yBin = h2->GetYaxis()->FindBin(c);
auto xProjection = h2->ProjectionX("pX", yBin, yBin);

I hope this helps!
Enrico