Chris Mc on Twitter is kind of amazed that a rather sophisticated graph like Julia Set can be generated using only 8 rows of data.
I am going to show that we can reduce that to 2 rows.

In visualizing math functions, usually we can use a fairly small data set as seed, such as 2 rows for one dimensional graphs or 8 rows for 3 dimensional graphs. The rest of data can be derived via data densification, a special tool in Tableau.

Basically the data densification allows us to create an indexed grid along each of the dimensions, on which the math functions will be drawn.

Usually we need 2^N rows of data as seed to create a N-dimensional data grid. For example, for a 3-d grid, we would start with a seed table of 8 rows like:
Just figured out a way to do it using 2 rows. Here it goes the steps:

- Create 2 rows in a single columns: (the other columns are all calculated fields.)
  • Seed
  • 1
  • 2
- Create any dimensions as follows. Say there are 3 dimensions x_basey_basez_base. Each of them can be created using the following formula: (This will define the range of each dimension.)
  • Case [Seed]
  • When 1 then 1
  • When 2 then [points]
  • End
This defines the range of dimension x_base from 1 to a dynamic parameter [points]. This is from an example on Julia Set visualization.

- Create bins for each of x_base, y_base, z_base with step size 1.

- Drag x_base(bin)y_base(bin), z_base(bin), to the Details shelf. These bins are the bases for data densification.

- Create Index() and drag it to the Details shelf. Set it to compute along all dimensions: x_base(bin)y_base(bin),   z_base(bin). This will trigger the data densification in all 3 dimensions. This is the most consistent way to do it. It took a while for me to figure this out because it can be tricky to trigger the densification.

Voila the above are the essential steps for creating a 3-dimensional grid through data densification. The size of each dimension can be fixed or dynamic.

See examples in creating the Julia set and Mandelbrot set.

Conclusion
For visualizing mathematical functions, all you need is 2 rows of data as seed. You can derive the rest. A great benefit of this approach is being able to use parameters to explore various combinations, because we can create data sets on the fly.
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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. 

Below I would like to show how this worksheet can be constructed.

1. Sheet with a single data mark.

  • Double click the empty space in Marks panel and add two single quotes. Make the null pill a text label. This creates a single null mark.
  • Set the view as "Entire View"

2. Create an show/hide button

  • Go to the target dashboard
  • Drag a floating vertical container to the dashboard, making it cover all the area of interest.
  • Drag the Single Null Mark sheet and drop it into the above container. Hide the sheet title.
  • Create an open/close button for the container and place the button at the top-right corner.

3. Add annotations

  • Format the sheet background opacity as 70% in the layout manager             
  • Select area annotations and place them anywhere of interest. 
  • Write help text and format it to highlight important messages.  
  • The text can serve as functional guide and/or insight guide.

Here is an example. Feel free to download the workbook and explore. Click the "i" button at the top-right corner to view the in-place help. 

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