Title for colorbar in Plotly Heatmap

Question

This is my code:

fig = go.Figure(
    data=go.Heatmap(z=z_values, y=[str(x) for x in params_1], x=[str(x) for x in params_2]), 
    layout=go.Layout(
        title="Analysis results",
        xaxis=dict(title='Diameter'),
        yaxis=dict(title='Max Distance')
    ),
)
fig.show()

It generates a 2D-heatmap (snippet below), but I'd like to include a title for the colorbar:

Unfortunately the plotly example also does not have a colorbar title. I have tried to include the colorbar properties with the "marker" but this throws an error. How can I do that hence?

score 15 · Answer 1 · answered Nov 26 '19 at 22:37

15

Just include colorbar={"title": 'Your title'} in go.Heatmap() to get this:

Plot:

Code:

import plotly.graph_objects as go

fig = go.Figure(data=go.Heatmap(colorbar={"title": "Your title"},
                                            z=[[1, 20, 30],
                                              [20, 1, 60],
                                              [30, 60, 1]]))
 fig.show()

answered Nov 26 '19 at 22:37

vestland

55,229
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1

@S3DEV You're welcome =) – vestland Jun 22 '23 at 21:01

abhilb · Accepted Answer · 2019-11-26T22:27:50.873

13

Try

fig = go.Figure(
    data=go.Heatmap(z=z_values, y=[str(x) for x in params_1], x=[str(x) for x in params_2]), 
colorbar=dict(title='Title') , 
    layout=go.Layout(
        title="Analysis results",
        xaxis=dict(title='Diameter'),
        yaxis=dict(title='Max Distance')
    ),
)
fig.show()

edited Nov 26 '19 at 22:27

answered Nov 26 '19 at 21:46

abhilb

5,639
2
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26

I get this then: File "", line 19 colorbar=dict(title=‘Title’) ^ SyntaxError: invalid character in identifier – TestGuest Nov 26 '19 at 22:03
Then changed ‘Title’ to 'Test' (different hyphens) but got: ValueError: Invalid property specified for object of type plotly.graph_objs.Layout: 'colorbar' – TestGuest Nov 26 '19 at 22:07
Updated the answer – abhilb Nov 26 '19 at 22:28

score 8 · Answer 3 · answered Jul 13 '20 at 18:25

8

You can also do it after by updating the layout:

fig.update_layout(
    coloraxis_colorbar=dict(
        title="Your Title",
    ),
)

answered Jul 13 '20 at 18:25

Piotro

525
5
5

did NOT work for me... plotly==5.9.0 – Julian - BrainAnnex.org Aug 28 '22 at 00:33
1

@Julian-BrainAnnex.org -- I had a similar issue, but found that this works if you specify the coloraxis the heatmap should use. E.g. ``` fig = go.Figure() fig.add_trace(go.Heatmap(x=..., y=..., z=..., coloraxis='coloraxis')) fig.update_layout(coloraxis_colorbar_title='Your Title') ``` – Tim Child Sep 22 '22 at 17:45

score 3 · Answer 4 · answered Feb 17 '21 at 01:18

3

fig = ...
fig.layout.coloraxis.colorbar.title = 'Title<br>Here'

answered Feb 17 '21 at 01:18

Miladiouss

4,270
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2

This one is universal and works with px.imshow as well. You can edit the title more using standard plotly arguments here as well: `{'text':'Title', 'font':{'size':30}}` – lotrus28 Aug 23 '21 at 20:07
1

This works with all plotly express plots as well. Very helpful! – codeananda Apr 14 '22 at 06:07
did NOT work for me... plotly==5.9.0 – Julian - BrainAnnex.org Aug 28 '22 at 00:34
@Julian-BrainAnnex.org -- I had a similar issue, but found that this works if you specify the coloraxis the heatmap should use. E.g. ``` fig = go.Figure() fig.add_trace(go.Heatmap(x=..., y=..., z=..., coloraxis='coloraxis')) fig.update_layout(coloraxis_colorbar_title='Your Title') ``` – Tim Child Sep 22 '22 at 17:45

score 1 · Answer 5 · answered Jan 13 '22 at 15:36

1

None of these were working for me but doing this updated it without any issue:

fig = ...
fig.data[0].colorbar.title = "Title Here"

answered Jan 13 '22 at 15:36

DaPieDude

31
6

1

Works perfectly in plotly==5.9.0 If you do a `print(fig)` , you can see that the Figure object now contains `'data': [{'colorbar': {'title': {'text': 'Title Here'}},` etc Note that with this approach, we're back to adding the colorbar title in the *data* section, just as done in the chosen answer – Julian - BrainAnnex.org Aug 28 '22 at 00:38

Title for colorbar in Plotly Heatmap

5 Answers5