1) 如何在 Pandas Bokeh 中切换科学记数法（使用 plot_bokeh 函数）和 2）如何将颜色居中于 0（所以白色为 0）

Question

I have some dataframe like this:

df = pd.DataFrame({
    'FSA': ['T9X', 'T2B', ...],
    'vals': [-1.1, 2.2, ...]
    'geometry': [some elements of type shapely.geometry.polygon.Polygon]
})

Where I got the geometry boundaries from the 2016 Canadian census here: http://www12.statcan.gc.ca/census-recensement/2011/geo/bound-limit/files-fichiers/2016/lfsa000a16a_e.zip

And I am basically trying to make a census map with some statistics using this dataframe like so:

df.plot_bokeh(
      simplify_shapes=20000,
      category="vals",
      colormap='RdBu', 
      colormap_range=(np.min(df.vals), np.max(df.vals)),
      hovertool_columns=["FSA", "vals"],
      figsize=(800, 800),
      title='Vals per FSA'
  )

I've tried looking in the docs for Bokeh and all over the place and can't really find how to standardize the colours so 0 (white) is in the middle of the colours, and negative values are red/positive are blue. Also, how do I turn off scientific notation? Any help is much appreciated :)

Answer 1

This doesn't help with creating a custom color ramp, but one thing you can do to "cheat" and put 0 in the middle and get it to be white is to use your min (or max, or some other arbitrary end point on either end, as long as they are the same) on both sides of of the colormap_range. So depending on how you want to represent the data (either way values will be clumped in one of the far ends of the color map). So it's not an ideal solution but would be one way of doing it.