Overlapping colorscales in plotly

Question

I have plotted a figure with 2 subplots, each with different scales. Everything plots correctly, except the colorscales are both plotted on the right and completely overlap - they are are not readable. I cannot find out how to position/reposition the individual subplot scales. I have included my code below. Thanks.

import pandas as pd
import plotly.graph_objects as go
from plotly.subplots import make_subplots

df = pd.read_csv(entry)
custColorscale = [[0, 'green'], [0.5, 'red'], [1, 'rgb(50, 50, 50)']]

fig = make_subplots(
    rows=1, cols=2, subplot_titles=('one', 'two'))

fig.add_trace(
    go.Scatter(x=df['tO'],
               y=df['t1'],
               mode='markers',
               marker=dict(colorscale=custColorscale,
                           cmin=0, cmax=2,
                           size=6, color=df['Var1'],
                           showscale=True),
               text=df['Var2']),
    1, 1)

fig.add_trace(
    go.Scatter(x=df['tO'],
               y=df['t1'],
               mode='markers',
               marker=dict(
        size=6, color=df['Var2'],
        showscale=True),
        text=df['Var2']),
    1, 2)

fig.update_layout(height=700, width=1900,
                  title='Raw data')
fig.update_layout(coloraxis=dict(
    colorscale='Bluered_r'))
fig.write_html(fig, file='raw plots.html', auto_open=True)

Answer 1

Looking through the Plotly documentation you find this which provide some hints as to how to solve the problem. Scroll to the 'marker' attributes and you will find that it has sub-attribute called 'colorbar'. The colorbar in turn has multiple options that could help set the plot the way you want. Particularly you find the 'x', 'y' and 'len' attributes of the colorbar very useful. You can use them to position the scales.

This question is also related to this but for a contour plot - you are making a scatterplot which is why the scatterplot reference would be what one should search.

A minimal working example (MWE) is shown below but with a toy dataset.

## make necessary imports
import numpy as np
from plotly.subplots import make_subplots
import plotly.graph_objects as go
import pandas as pd

## make a fake dataset with pandas

d = {'t0': [i for i in np.arange(0.,10.,1.)], 't1': [i for i in 
    np.arange(10.,20.,1.)],'Var1': [i for i in np.arange(20.,30.,1.)],'Var2': 
   [i for i in   np.arange(30.,40.,1.)] }

df = pd.DataFrame(data=d) #the dataset is made to mock the example code you provided

And for your plot you have the following :

# make subplots

 custColorscale = [[0, 'green'], [0.5, 'red'], [1, 'rgb(50, 50, 50)']]
 fig = make_subplots(
 rows=1, cols=2, subplot_titles=('one', 'two'),horizontal_spacing = 0.4)
 
 # plot 1
 fig.add_trace(
    go.Scatter(x=df['t0'],
           y=df['t1'],
           mode='markers',
           marker=dict(colorscale=custColorscale,
                       cmin=0, cmax=2,
                       size=6, color=df['Var1'],
                       showscale=True,colorbar=dict(len=1.05, x=0.35 
                  ,y=0.49)), text=df['Var2']), 1, 1)
## plot 2
fig.add_trace(
   go.Scatter(x=df['t0'],
           y=df['t1'],
           mode='markers',
           marker=dict(
    size=6, color=df['Var2'],
    showscale=True,colorbar=dict(len=1.05,  x=1.2  , y=0.49)),
    text=df['Var2']), 
    1, 2 )
# show plots
fig.update_layout(height=500, width=700,
              title='Raw data')
fig.update_layout(coloraxis=dict(
           colorscale='Bluered_r'))

fig.show()

The only additions were:

1. The colorbar attribute of the marker.

2. The horizontal spacing to allow space for the first scale.

Feel free to play with these attributes.

I hope this helps!

Best regards.