There are always more than one ways to skin a cat. In Tableau, there is always one more way to design the same chart. Mastering them will give us more options to satisfy the various requirements we may be asked for.

Line chart is one of the most basic ones. Yet we can draw them in more ways than we care of. But there are many intricacies that are interesting to master.

In graphical design, every tiny bit of space counts because the canvas may be limited or because of alignment with other parts of the dashboard. In this post, we are going to show how to design line charts with minimum axis offset.

Axis Offset with Date in Columns Shelf

This is the default way of creating a line chart. One can notice that there exists always a horizontal offset at the first data mark from the vertical axis. With continuous date, the offset is big. With discrete date, there is half a tick offset. We have no way to edit the offset. 

Note that we dual axis'ed the line chart with an area chart to emphasize both the trend and the volume.

Note that with discrete date, we need to turn on "Show missing values" to create the correct line chart.

Axis Offset with INDEX() in Columns Shelf

To have more control over the axis offset, we can place continuous  INDEX() in the Columns shelf and the date dimension in the Detail shelf. Set INDEX() to compute along the date dimension.

An important caveat is we need to first set up the date dimension on Rows/Columns and turn on "Show missing values". Then drag it to the Detail shelf. This guarantees correct indexing even though we don't have contiguous data.

Edit the axis to be fixed start at 1, and end with automatic.

Now we have the line start at the vertical axis. The offset is 0 which is the least.
We can still have INDEX() in discrete. The offset is the same as the chart with discrete date in Columns.

Line Chart Multiples with INDEX()

We may need to create line chart multiples when splitting a line chart per category (State in the following example). We still like to create them with continuous INDEX() in the Columns shelf so that we have zero axis offset. Then we need to set up the date dimension with "Show missing values" in the Columns shelf before moving it to the Detail shelf.

A very important addition here is to place an INDEX() in the Detail shelf. Then set up its table calculations along the date dimension first and State second (Respect the order pls). 

The 2-dimensional INDEX() is part of the data densification technique. We may not have all the data points at all dates and all states. This INDEX() in the Detail shelf will create a 2-d grid by Date and State. This will guarantee that each line chart per state will be indexed correctly by INDEX() in the Columns shelf. 

After the splitting by state, it is more likely that each line will miss some data at some dates.

Without the two dimensional INDEX(), the line chart multiples will look like this. All lines will start at INDEX()=1. This is not correct.

Summary

In case a viz design requires that the line chart start with zero axis offset, we showed above that we can do it with Continuous Index in the Columns shelf. And in case we need to create line chart multiples with zero axis offset, we can add a two-dimensional INDEX() to achieve it.

The demo workbook can be downloaded from here.


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Jake and I collaborated on a dashboard. He told me that he learnt a way to create an in-place help page in Tableau. He first saw it at a conference somewhere and couldn't recall who the speaker was. So I am blogging here about it but the credit goes to somebody else. If anyone knows who the original creator is, leave a comment below.

The key idea is to float a semi transparent worksheet on top of the dashboard, where a help text box is strategically placed on top of each chart. This way, we can explain how to view each chart and what data points are important, etc. This worksheet is collapsible by a show/hide button.

(Addendum: Jonathan Drummey has a much better Tableau-only solution that I missed from his presentation. I only caught later part of the presentation. You might ask him about it if you know him.)

In a recent presentation, Tableau visionary HOF Jonathan Drummey talked about a solution for a variable row heights in a text table. The question apparently came from a perfectionist tableau designer. Tableau is not really made for text processing.

[Forward: I asked ChatGPT o1-mini who then wrote this. Hope it helps. All the credit and the blame go to ChatGPT.

I went over the plan and it looked decent. Whether it can be done in 30 days or not, it depends on the person and the time he spends on it. By the way, ChatGPT can be a really good study buddy. Ask it questions whenever you have any.]

This comprehensive 30-day plan is designed to take you from a Tableau beginner to an advanced user.

Mundane charts are those basic ones that all data visualization beginners can create, possibly with Show Me in Tableau. They are the boring ones at times because many people tend to create fancier ones just to show off. 

I actually like the mundane ones a lot because they are not only easy to create but also easy to be read by the stakeholders.

Pareto chart is a very powerful tool, providing great insights into the data set and into the business at stake.

A while ago, Sharon came to me asking a question regarding Pareto Chart Multiples. That is, per each category, there is a Pareto chart. And we need to create Pareto charts for all the categories. This chart allows us to quickly view the few most important factors that matter to the majority of output in each category. 

Vilfredo Pareto (1848-1923) is the father of the 80/20 rule: 80% of output are produced by 20% of input. It works magically well through all the years.

[Update: The product manager Wilson Po alerted me that the Viz Extension is still a work in progress. It will not be part of the incoming version 2024.1. Instead, it will be released later in 2024. Just be patient]

Tableau 2024.1 is coming. I got a chance to test drive it. As I wrote a bunch of posts on Sankey chart tutorials in the past, I am most excited by the new Sankey chart type. Here I would like to share what I learnt. This is a quick preview. Your comments are welcome.

Buzzfeed recently asked Midjourney to draw images of people in 50 US states.  So the AI drawing tool created 50 images of couples that represent its perception of the people in each state.

I just put the images into a tiled map in Tableau. Each image is added as a background in each tile.

And also I added Viz-in-tooltips to enlarge an image to look at more details.

Feel free to download the workbook and explore it.
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The folks at Business Expert had a brilliant idea. They asked AI's perception on UK banks as a dog. I am inspired to do the same on US banks.

ChatGPT is asked to confess its perceptions on top US banks as a dog. Then Midjourney is tasked to generate the images. Check out what dog is matched to your favorite bank.

All are put together into a single-sheet Tableau dashboard. Feel free to check it out.

Through my previous post on the new Sankey chart type, I got in touch with Wilson, the product manager leading the development of this new chart type. I made some comments on creating multi-level Sankey via cascading of single Sankey's. He told me it can be done already by dropping more dimensions into the Level card.

As an enthusiastic user of Sankey charts, I am excited to learn that a Sankey chart type is being piloted in Tableau Public (Web Edit only). I wrote about Sankey chart design in multiple posts. Sankey chart may appear in different forms depending on applications. 

I played a little with it just to evaluate it. Here are my initial findings and comments.

1. The basic Sankey

I can quickly create a Sankey with 2 dimensions and 1 measure.
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