Is your feature request related to a problem?

In portrait_plot_lib.py, prepare_data() (lines 343-387), NaN values are masked out and replaced with 1e20, showing interactive portrait plot tooltip values as 0 and glyphs in yellow.

Describe the solution you'd like

Values should remain NaN to use bokeh parameter nan_color=missing_color. Tooltip values should be NaN and glyphs should be missing_color (grey). I propose removing line 385 that creates a masked array. This is not necessary as other functions (i.e., normalize_by_median() ) already ignore NaNs.

Describe alternatives you've considered

I considered setting the masked array fill value to NaN, but this does not correctly map the glyphs to the correct color and is likely redundant.

Additional context

No response