[BUG/ISSUE] Colorbar ticks are incorrectly placed if the plot is zero or undefined everywhere. about gcpy HOT 2 CLOSED

This issue is now resolved in 1c7647a. We now test whether or not we are using matplotlib 3.1.1 or an older version, and adjust the tickmark placement accordingly.

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I have now pushed commit: f450fe2, which definitively fixes this issue.

The problem was not so much matplotlib 3.1.1 vs. older versions,. Instead, if we use the RdBu colortable (as we do for diff-of-diffs plots, like the one shown above), then we must take care to place the tick in the middle of the colorbar if Ref and/or Dev is zero or undefined everywhere. I modified the code in the if all_zero or all_undefined blocks accordingly.

        if all_zero or all_undefined:
            if use_cmap_RdBu:
                cb.set_ticks([0.0])
            else:
                cb.set_ticks([0.5])

This now produces the proper tick placement for RdBu difference color map:

As well as the non-difference color map WhGrYlRd:

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