Plotly Polar Bar Plot - setting custom theta unit

Question

I am fairly new to plotly and and attempting to make a polar bar plot in which the theta values correspond to hours in a day. For example:

0°/360° -> 00:00

90° -> 06:00

180° -> 12:00

270° -> 18:00

Here is my code: I have a pandas datframe called "bins" which records the occurences of data entries within that hour time slot:

    index   justtime
0   20  5163
1   21  5007
2   19  4873
3   23  4805
4   0   4587
5   22  4565
6   18  4376
7   1   4101
8   17  4063
9   3   4014
10  2   3972
11  4   3840
12  16  3272
13  5   3239
14  15  2688
15  6   2626
16  7   1988
17  14  1740
18  8   1111
19  13  853
20  9   466
21  12  416
22  10  413
23  11  339

Then I have some code to make the plotly graph:

fig = go.Figure(go.Barpolar(
    r= bins['justtime'],
    theta= [x*15 for x in bins['index']],
    width= [14 for x in bins['index']],
    marker_line_color="black",
    marker_line_width=2,
    opacity=0.8
))

fig.update_layout(
    template=None,
    polar = dict(
        radialaxis = dict(range=[0, bins['justtime'].max()], showticklabels=False, ticks=''),
        angularaxis = dict(showticklabels=True, type='linear', thetaunit='', categoryorder = 'array', categoryarray = [x for x in bins['index']])
    )
)

fig.show()

which produces this:

Instead of showing theta degrees in the axis labels around the circle, I would like to show the true hour time which would be bins['index'].

I have played around with the angularaxis arguments but cannot figure it out.

I'm sure it's fairly simple and I am overlooking it, any help would be appreciated.

Answer 1

• have used Plotly Express instead of graph objects
• have re-expressed hour as degrees in data frame
• included hover_data so it's simpler for user
• defined ticks in layout

import pandas as pd
import io
import plotly.express as px

bins = pd.read_csv(io.StringIO("""    index   justtime
0   20  5163
1   21  5007
2   19  4873
3   23  4805
4   0   4587
5   22  4565
6   18  4376
7   1   4101
8   17  4063
9   3   4014
10  2   3972
11  4   3840
12  16  3272
13  5   3239
14  15  2688
15  6   2626
16  7   1988
17  14  1740
18  8   1111
19  13  853
20  9   466
21  12  416
22  10  413
23  11  339"""), sep="\s+")

# add another column which is hour converted to degrees
bins = bins.assign(r=(bins["index"] / 24) * 360)
fig = px.bar_polar(bins, r="justtime", theta="r", hover_data={"Hour":bins["index"]}).update_traces(
    marker={"line": {"width": 2, "color": "black"}}
)

labelevery = 6
fig.update_layout(
    polar={
        "angularaxis": {
            "tickmode": "array",
            "tickvals": list(range(0, 360, 360 // labelevery)),
            "ticktext": [f"{a:02}:00" for a in range(0, 24, 24 // labelevery)],
        }
    }
)