Plotly.Express.Timeline()

Timeline plots, commonly known as Gantt charts, are types of charts used to visualize a schedule. It is commonly used to show a list of tasks that needs to be executed on a vertical axis and the time interval on the horizontal axis.

Let us explore how we can create the Timeline Plots with the Plotly Express module.

Plotly.express.timeline()

To create a Gantt chart in Plotly, we use the timeline() function. The function syntax and parameter list are as shown in the following:

The parameters are expressed as follows:

1. data_frame – Specifies the data frame containing the columns used in the plot.
2. x_start – Specifies the values used in the position marks along the x axis in the cartesian plane. You can specify these values as a column within the data_frame or a Pandas Series.
3. x_end – Similar to x_start.
4. y – Similar to x_start and x_end but the values in this parameter are used to position the marks along the y axis in the Cartesian plane.
5. color – Specifies the value used assign a unique color to the marks of the plot.
6. title – Sets a title for the plot.
7. width/height – Sets the width and height of the figure in pixels.

The function creates a Gantt plot of the specified values as graph_objects.Figure type.

Basic Gantt Chart

Let us create a simple Gantt plot to illustrate how we can use the timeline() function.

The given code creates the Gantt figure of the provide data as shown in the following illustration:

Plotly Gantt Set the Discrete Color

You can set a discrete color for each bar by setting the color parameter. For example, to set a unique color for each project, we can run the following code:

In this case, we set the color parameter to the Task column within the DataFrame.

This returns the following figure:

To create the title for the Gantt chart, we can use the title parameter as shown in the following code:

This sets the string as the title for the figure as shown in the following:

To add a text inside the bar plots, we can use the text parameter as shown in the following:

The resulting figure is as follows:

To set the width and height of the figure, you can use their respective parameters as shown in the following:

The resulting figure takes the specified dimensions despite the environment screen real estate.

Conclusion

In this article, we discussed how you can create a Gantt chart using the Plotly Express timeline() function.