Is there a way to use Plotly as an annotation tool, for labelling time-series for instance?

Question

I have been tasked to create a tool aimed at labelling sections and/or precise data points of a biomedical time-series. Our main framework is written in Python.

I would like to know whether it is possible to do it with Plotly, and if so, would someone mind sharing their experience?

Kind regards, Bertrand

score 0 · Accepted Answer · answered Dec 06 '22 at 16:06

Yes, it is possible to use Plotly as an annotation tool for labelling time-series or other data. Plotly provides a range of annotation options, including text annotations, shapes, and arrows, which can be used to label specific points or regions in a plot.

Plotly Annotation Features:

The Annotations feature, allows you to add text labels or notes to specific points on the plot.
The Annotations Editor, provides a user-friendly interface for adding and editing annotations on the plot.
The add_annotations() function, which allows you to programmatically add annotations to the plot using Python or R code.

To use Plotly as an annotation tool, you can first create a time-series plot using the plotly.express or plotly.graph_objects functions. Then, you can use the add_annotation() method to add annotations to the plot. This method allows you to specify the x and y coordinates of the annotation and the text, color, font size, and other attributes of the annotation.

For example, to add a text annotation to a time-series plot, you could use the following code:

import plotly.express as px
df = px.data.gapminder()
fig = px.line(df, x="year", y="lifeExp", color="continent")
fig.add_annotation(x=1970, y=70, text="Annotation text",
                   font=dict(size=16), arrowcolor="red")
fig.show()

This code would create a line plot of life expectancy over time, and add a text annotation at the point (1970, 70) with the text "Annotation text" and a red arrow pointing to that point.

or you can use the annotations attribute of the layout object in Plotly. This attribute is a list of annotations, where each annotation is a dictionary containing the information for a single annotation, such as the text to display and the position of the annotation. Here is an example of how you can use the annotations attribute to label the time-series data in a Plotly chart:

import plotly.express as px
Generate some dummy time-series data
df = px.data.gapminder().query("continent == 'Oceania'")
Create a line chart of the time-series data
fig = px.line(df, x="year", y="gdpPercap", color="country")
Add annotations to the chart
fig.update_layout(
    annotations=[
        dict(
            x=1955,
            y=10000,
            text="Annotation 1",
            showarrow=True,
            arrowhead=7,
            ax=0,
            ay=-40
        ),
        dict(
            x=1975,
            y=20000,
            text="Annotation 2",
            showarrow=True,
            arrowhead=7,
            ax=0,
            ay=-40
        ),
    ]
)
fig.show()

More examples from official Plotly documentation : Text and annotations in Python - Plotly

Overall, Plotly provides a range of tools and options for annotating time-series or other data, allowing you to easily label specific points or regions in your plots.

Is there a way to use Plotly as an annotation tool, for labelling time-series for instance?

1 Answers1

Generate some dummy time-series data

Create a line chart of the time-series data

Add annotations to the chart