I want to make a 2-D polar histogram.
The bin edges will be evenly spaced in radius.
But there will be an arbitrary number of angle bins at a given radius.
The only class I know to make bins with arbitrary shapes is the TH2Poly class.
So I want to use this and plot it in polar coordinates using the “pol” option.
I am using ROOT version 5.34/19.

actually you don’t need a TH2Poly here. It seems what you want are not arbitrary shapes, but just arbitrary bin borders. The TH2F allows you to do that already. See this answer to a similar problem:
[url]TH2F polar coordinates binning

Thank you for your answers.
Forgive me if I am mistaken, but I am interested in an arbitrary number of angle bins at a given radius.
I don’t think the TH2F class allows this as the variable bin edges in the angle axis will be applied to all bins in the radial direction.
I am attempting this because I want the size of the bins to be relatively constant as the radius increases. So at a small radius, there will be only a few angle bins, but at a larger radius, there will be more.