Toan Hoang

Creating Half Circle Timelines Variation in Tableau

Toan Hoang

Someone reached out to me and asked me if I could help him visualise several milestones in his career using my initial Half Circle Timelines tutorial. My previous tutorial had equal spacing, so this time, I ensure that the circles were spaced relative to the timeline and sized based on the duration.

Note: This is an alternative type of data visualisation, and sometimes pushed for by clients. Please always look at best practices for data visualisations before deploying this into production.

Data

To get started, load the following data into Tableau Public / Tableau Desktop

Activity,From,To
High School,06 Sep 1993,21 May 1998
A-Levels,07 Sep 1998,19 May 2000
University,18 Sep 2000,20 May 2004
First Job,07 Jul 2004,16 Jun 2006

Once your data is loaded into Tableau, right-click on the data source and click on Edit Data Source… with the Data Source Editor open, paste the following:

Path
0
180

Note: If you are using Tableau 2020.2 or great i.e. have access to new Relationship Model, you will need to double-click on the originally pasted data source to open up before pasting in the Path Data.

You should get an error as there is no joining column, however, click on Add new join clause, go to Create Join Calculation, type 1 and click OK. Do this for the right-hand side as well. Ensure that you have Inner join selected and you should see the following:

Calculated Fields

With our data set loaded into Tableau, we are going to create the following Calculated Fields and Bins:

Path (bin)

Index

// Index function to start at zero
INDEX()-1

TC_From

// Wrapping the from date in a Windows Function
WINDOW_MAX(MAX([From]))

TC_To

// Wrapping the to date in a Windows Function
WINDOW_MAX(MAX([To]))

TC_Radius

// Find the number of days between the two dates
// and then divide the number by 2 to get the radius
DATEDIFF("day", [TC_From], [TC_To])/2

TC_Center Date

DATEADD("day", [TC_Radius], [TC_From])

TC_Center Date by Day

DATEDIFF("day", #01/01/1900#,[TC_Center Date])

X

(COS(RADIANS([Index]))*[TC_Radius])+[TC_Center Date by Day]

Y

SIN(RADIANS([Index]))*[TC_Radius]

TC_Label Activity

IF [Index] = 90 THEN
    WINDOW_MAX(MAX([Activity]))
END

TC_Label From

IF [Index] = 90 THEN
    [TC_From]
END

TC_Label To

IF [Index] = 90 THEN
    [TC_To]
END

With this done, let us start creating our data visualisation.

Worksheet

We will now build our worksheet:

If all goes well, you should now see the following:

We will now add a dual axis line in order to get our label onto of our half circles.

You should now have the following:

Now, we will finish off our data visualisation:

You will want to end up with the following:

and boom, we are done! Now give this a try with your own personal timeline, and do let me know how it goes. I hope you enjoyed creating this data visualization and learned some cool techniques as well. As always, you can find this data visualisation on Tableau Public at https://public.tableau.com/profile/toan.hoang#!/vizhome/HalfCircleTimelineVersionTwo/HalfCircleTimelineVersionTwo

Summary

I hope you all enjoyed this article as much as I enjoyed writing it and as always do share the love. Do let me know if you experienced any issues recreating this Visualization, and as always, please leave a comment below or reach out to me on Twitter @Tableau_Magic. Do also remember to tag me in your work if you use this tutorial.

If you like our work, do consider supporting us on Patreon, and for supporting us, we will give you early access to tutorials, exclusive videos, as well as access to current and future courses on Udemy: https://www.patreon.com/tableaumagic

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