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Totally Useless Charts & How to Build Them – “Hand-drawn” Bar Charts

The second installment of the Totally Useless Charts & How to Build Them series, walks through how to use the Line mark type to create “hand-drawn” bar charts.

Welcome to our 2nd installment of Totally Useless Charts & How to Build Them, where we do…exactly what the name implies. Look at some totally useless charts and walk through, step by step, how to build them. If you missed the first installment, the goal of this series isn’t necessarily to teach you how to build these specific useless charts, but more to talk through the techniques, the approach, and the thought process behind each chart, so you can apply those concepts to your own custom charts.

In this installment we’re going to learn how to build “hand-drawn” bar charts in Tableau. These of course aren’t actually hand-drawn, but using some interesting techniques, and a lot of random numbers, we can kind of make them look that way. If you would like to follow along, you can download the workbook here, and the data here.

“Hand-Drawn” Bar Charts

First, let’s look at an example of what we’re talking about. Here is a viz that I published recently about relationships on the show “The Office”. You can check out the interactive viz here.

My goal was to make the entire viz look like an office desk belonging to everyone’s favorite receptionist/office manager, Pam Halpert. To do that, I had to make all of the visualizations appear to be “hand-drawn”, including the bar charts. Let’s zoom in one those.

Here we have two different bar charts, one for the Longest Relationship, and one for the Most Time in Relationships (by number of episodes). Today we’re going to be using different data, but the goal is still the same…build some bar charts that look “hand-drawn”.

Building Your Data Source

Let’s start with our data. For this example we’re going to look at the top 10 highest grossing films of all time. If you downloaded the sample data, you can find these in the “Data” tab.

Next, we need to do some densification. The first thing we need to do is to create a record for every line needed in each bar. If you look at one of these bars closely, you’ll see that it’s actually made up of a bunch of lines…one outer line (orange), and a number of cross lines (blue).

So we are going to densify our data with our first densification table, called “Lines” in the sample data. In this table, we have 1 record for our Outer Line, and 50 records for our Cross Lines

Then we’re going to join our “Data” table, and our “Lines” table using a join calculation with a value of 1 on each side.

But we’re not quite done yet. Now we have a record for each of our lines, but each of those lines is made up of multiple points. Our “Outer Line’ is made up of 4 points, and each of our “Cross Lines” is made up of two points

So we’re going to use one more densification table to create additional records for each of these points, for each of the lines. This table is called “Points” in the sample data

And we’re going to join this to our “Lines” table on the [LineType] Field.

Now for each of our 10 films, we have 4 records for our “Outer Line” and 100 records for our “Cross Lines”, 2 for each of the 50 lines in the “Lines” table.

Drawing the “Outer Lines”

Now we have our data, let’s start building our Totally Useless Chart. We’re going to start with the Outer Lines. To do this, and to make it a bit dynamic so you can play around with how the chart looks, we’re going to build 4 Parameters. Each of these is going to have a Data Type of “Float” and the Default values are below

  • Bar_Width = .6 (used for the height of each bar and the spacing between the bars)
  • Scale_Bar_Outer_Height = .03 (used along with a random number to jitter points vertically)
  • Scale_Bar_Outer_Length = .1 (used along with a random number to jitter points horizontally)
  • Cross Lines = 50 (used to limit the number of cross-lines in each bar. This is optional)

Next, we’ll start building our calculations. The first, and arguably most important of these calcs is going to be our [Jitter] calculation. We want a random number between -1 and 1. The Random() function will give us a random number between 0 and 1, so we can modify that by multiplying the random number by 2 and then subtracting 1 (so a random number of .6 would become .2, and a random number .4 would become -.2)

Jitter = Random()*2-1

Next, we need to calculate the length of each of our “bars”. We’re going to do this by comparing each value to the maximum value and then multiplying it by the Max Length, which in our case will be the number of “Cross” lines we have. So the highest grossing film, Avatar, will have a length of 50, since we have 50 “Cross” lines. ((2.847B/2.847B)*50). Number 10 on the list will have a length of around 26.6 ((1.515B/2.847B(*50). So first, let’s calculate our Max length.

Max Length = {MAX([Line ID]}

Next, we’ll want to divide the Box Office Gross for each movie by the value for the highest grossing movie. The result of this will be a percentage which we’ll then multiply by our [Max Length] field to get our [Outer Bar Length]

Outer Bar Length = ([Box Office Gross]/{MAX([Box Office Gross])})*[Max Length]

Now, we need to calculate the X and Y coordinates for the 4 points of each “Outer Line”. So under normal circumstances, point 1 and point 4 would start at 0, and point 2 and point 3 would just be the [Outer Bar Length]. So if you connected those points, it would start at 0 for point 1, go to the end of the line for point 2, stay at the end of the line for point 3, and then return to 0 for point 4. But we want this to look “hand-drawn”, and if I was drawing bar charts by hand, there is no way they would align that neatly. That’s where our [Jitter] and “Scale” parameters come in.

Outer_Bar_X

CASE [Points]

WHEN 1 then 0+([Jitter]*[Scale_Bar_Outer_Length])

WHEN 2 then [Outer Bar Length]+([Jitter]*[Scale_Bar_Outer_Length])

WHEN 3 then [Outer Bar Length]+([Jitter]*[Scale_Bar_Outer_Length])

WHEN 4 then 0+([Jitter]*[Scale_Bar_Outer_Length])

END

We just want to move these points slightly to get that “hand-drawn” effect, which is why we are using the “Scale” parameters. For that first point, if we just did 0+[Jitter], that value could fall anywhere between -1 and 1, which is a pretty significant shift. But using the [Scale_Bar_Outer_Length] parameter, we can increase that value to get more jitter, or decrease the value to get less jitter. Using a value of .1 in the parameter, means that the value for that first point would now fall somewhere between -.1 and .1.

Next, we need to calculate our Y coordinates for those same 4 points. Again, under normal circumstances, for point 1 we would add half of the bar width to our starting point (the middle of the bar), same for point 2, and then for points 3 and 4, we would subtract half of the bar width from the starting point. So, along with the X coordinates, it would look something like this.

This is where the [Bar_Width] parameter comes into play. We need to know how thick these bars should be. We’re using the [Rank] field as our starting point, so the first bar will start 0,1, the second bar will start at 0,2, and so on. But we don’t want the bars to overlap, or be right up against each other, so we can control that with the parameter. A larger value in this parameter will result in wider bars and less spacing, a smaller value will result in skinnier bars, and more spacing. A value of 1 will result in no spacing between the bars.

Also, similar to the calculation for the X coordinates, we are using that [Jitter] field along with a “Scale” parameter to control how much jitter there will be. So a larger number in the [Scale_Bar_Outer_Height] parameter will result in more vertical jitter, and a lower number will result in less. Here is the calculation for the Y coordinates.

Outer_Bar_Y

CASE [Points]

WHEN 1 then [Rank]+([Bar_Width]/2)+([Jitter]*[Scale_Bar_Outer_Height])

WHEN 2 then [Rank]+([Bar_Width]/2)+(([Jitter]*[Scale_Bar_Outer_Height])2)

WHEN 3 then [Rank]-([Bar_Width]/2)+(([Jitter]*[Scale_Bar_Outer_Height])2)

WHEN 4 then [Rank]-([Bar_Width]/2)+([Jitter]*[Scale_Bar_Outer_Height])

END

Now we have all of the calculations needed to draw our “Outer” lines. So let’s do that

  • Drag [Line Type] to the filter shelf and filter on “Outer Lines”
  • Right click on [Outer_Bar_X], drag it to Columns, and when prompted, choose [Outer_Bar_X] without aggregation
  • Right click on [Outer_Bar_Y], drag it to Rows, and when prompted, choose [Outer_Bar_Y] without aggregation
  • Change the Mark Type to “Line”
  • Right click on [Rank], select “Convert to Dimension” and then drag [Rank] to Detail
  • Right click on [Points], drag it to Path, and when prompted, choose [Points] without aggregation
  • Right click on the Y-axis, select “Edit Axis”, and check the box labelled “Reverse” under Scale

When that’s finished, you should have something that looks like this. There are 10 “bars”, with all 4 points in each bar slightly jittered to give it that “hand-drawn” look.

Next, we need to add the “Cross Lines”

Drawing the “Cross Lines”

To help understand the approach we’re going to take, think about taking each of these bars and breaking them into individual segments. So, for example, our first bar has a length of 50 (think back to the Max Length calculation). So we want to break that into 50 individual segments and draw a diagonal line from the top left of the segment to the bottom right of the segment.

The image above is roughly what it would look like if we draw perfect lines across those segments. But we don’t want perfect lines. We want “hand-drawn” lines. So we’re going to leverage our [Jitter] field and our “Scale” parameters once again.

So let’s build our X and Y calculations. Remember when we built our data source, for our “Cross Lines”, we needed two points, 1 and 2. So Point 1 is going to start the line at the top left of our segment, and Point 2 is going to end the line at the bottom right of our segment. Here is the calculation

Cross_X = if [Points]=1 then [Line ID]-1 + ([Jitter]*[Scale_Bar_Outer_Length]*2) else [Line ID]+([Jitter]*[Scale_Bar_Outer_Length]*2) END

Here we are calculating the position for both points on the X axis. For the first point, when [Points]=1, we want to use our [Line ID] value and subtract 1, so we’re starting at the beginning of our segment (ex. line 1 will start at 0, line 2 will start at 1, line 3 will start at 2, and so on). When [Points]=2, we are going to use just the [Line ID] value (ex. line 1 will end at 1, line 2 will end at 2, line 3 will end at 3). And then we’re just using our [Jitter] field and our “Scale” parameter to jitter these points a little bit, similar to what we did with the “Outer” lines. You may notice that there is a “*2” in these calculations. I added these so I could re-use my same parameters, but could add a little extra jitter to the Cross Lines. I figured if these were actually being done by hand there would be a lot more variation in these lines, compared to the “Outer” lines.

Now let’s calculate our Y coordinates. Similar to how we calculated the Y coordinates for the “Outer” lines, we want one of our points to be half the width of the bar above our starting point, and the other one, half the width of the bar below the starting point. And then we want to jitter them. Here’s the calculation for the Y coordinates.

Cross_Y = if [Points]=1 then [Rank]-([Bar_Width]/2)+([Jitter]*[Scale_Bar_Outer_Height]*2) else [Rank]+([Bar_Width]/2)+([Jitter]*[Scale_Bar_Outer_Height]*2) END

Now this is a little bit confusing because we reversed our axis in an earlier step. So, for Point 1, instead of adding half of the width of the bar to our starting point, the [Rank] field, we need to subtract it from the starting point, to get it to appear above the bar (because the axis is reversed). So when [Points]=1 we’ll subtract half of the width of the bar ([Bar_Width]/2) from the starting point, [Rank]. When [Points]=2, we’ll add half of the width of the bar to the starting point. And then once again we’re using the [Jitter] field, the “Scale” parameter, and then multiplying by 2 to get a little extra jitter. If you wanted to reverse the direction of these lines, so they go from top right to bottom left, just change the calc so when [Points]=1 you add, and when [Points]=2 you subtract.

Now let’s build it.

  • Drag [Line Type] to the filter shelf and filter on “Cross Lines”
  • Right click on [Cross_X], drag it to Columns, and when prompted, choose [Cross_X] without aggregation
  • Right click on [Cross_Y], drag it to Rows, and when prompted, choose [Cross_Y] without aggregation
  • Change the Mark Type to “Line”
  • Right click on [Line ID], select “Convert to Dimension” and then drag [Line ID] to Detail
  • Right click on [Rank], select “Convert to Dimension” and then drag [Rank] to Detail
  • Right click on [Points], drag it to Path, and when prompted, choose [Points] without aggregation
  • Right click on the Y-axis, select “Edit Axis”, and check the box labelled “Reverse” under Scale

Once complete, you should have 50 “Cross Lines” for each of your “bars”.

Now we just need to bring it all together

Combining the Lines

We have our “Outer” lines, and we have our “Cross” lines, and because we have separate data points for each of these (because of the way we structured our data) we can bring them together in the same view pretty easily. We just need to 2 more “Final” calculations for the X and Y coordinates.

Final_X = if [Line Type]=’Outer Lines’ then [Outer_Bar_X] else [Cross_X] END

Final_Y = if [Line Type]=’Outer Lines’ then [Outer_Bar_Y] else [Cross_Y] END

These are pretty straightforward, but basically, if the [Line Type]=”Outer Lines” use the X and Y values from the “Outer_Bar” fields. Otherwise, use the X and Y values from the “Cross” fields. Now let’s build our “bars” with these “Final” calcs.

  • Right click on [Final_X], drag it to Columns, and when prompted, choose [Final_X] without aggregation
  • Right click on [Final_Y], drag it to Rows, and when prompted, choose [Final_Y] without aggregation
  • Change the Mark Type to “Line”
  • Right click on [Line ID], select “Convert to Dimension” and then drag [Line ID] to Detail
  • Right click on [Rank], select “Convert to Dimension” and then drag [Rank] to Detail
  • Drag [Line Type] to Detail
  • Right click on [Points], drag it to Path, and when prompted, choose [Points] without aggregation
  • Right click on the Y-axis, select “Edit Axis”, and check the box labelled “Reverse” under Scale

And now you should have everything together on the same view!

Wait…that doesn’t look right. We don’t want all of those extra “Cross” lines on our shorter bars. Luckily, we can filter those out pretty easily with a calculated field. This is just a boolean calc that checks to see if the Line ID is less than the length of the bar. Remember from earlier that the Line ID corresponds to the right side, or the end of each of these “Cross” lines. So we only want to keep the lines where that value is less than the length of the bar.

Extra Lines Filter = [Line ID]<=[Outer Bar Length]

Now just drag the [Extra Lines Filter] field onto the Filter shelf, and filter on TRUE and voila!

There is one more step that’s completely optional. The way we set up this data source, we can have up to 50 “Cross” lines for the largest bar. But maybe you want less than that. I like to make my visualizations as dynamic as possible so I can play around with how it looks. Earlier we created a parameter called [Cross Lines]. We can use that parameter to determine how many lines we want to use. We’re just going to create one additional calculated field.

Max Cross Lines Filter = [Line ID]<=[Cross Lines]

Just drag that field onto the Filter shelf, filter on TRUE, and then right click on the pill and choose “Add to Context”. Now you can adjust the number of lines, and in doing so, the spacing between the lines. Here’s what it looks like with 30 lines instead of 50.

If you want to use more than 50 lines, just add some additional rows to the “Lines” densification table.

Final Touches

So now our view is built, but there is one critical piece of information missing from our chart…Row Labels. There are a few different ways you can add these, but I’m going to cover two quick options; Shapes and Labels.

For the viz that I shared earlier, I was publishing it to Tableau Public, which has pretty limited options when it comes to fonts, and I really wanted a “hand-drawn” font. What I ended up doing was creating custom shapes for each of my labels in PowerPoint. If you decide to go this route, one thing you want to make sure that you do is to set the size of each of the text boxes equal. If the text boxes are different sizes when you save them as images, it will look like the text is a different size for each value because Tableau will attempt to “normalize” them.

So first, create your shapes in PowerPoint. Here, I inserted 10 text boxes, typed my movie names, set the alignment to “Right”, and then set the Font to “Caveat”. Then I clicked and dragged to highlight all 10 text boxes, and in the top right corner of PowerPoint, in the Shape Format options, I set the “Width” so that they would all be the same size. regardless of how long the text in each box actually is.

Then I right-clicked on each image, saved them to a folder in my “Shapes” repository. Finally, I created a new sheet using the “Shapes” mark type, positioned them by Rank, and then fixed and reversed the axis so they would align with the bars. Then you can throw these two sheets in a container on your final dashboard and have something like this.

So that’s an option if your data is static and you don’t have a lot of values. This would be nearly impossible to maintain if new values were constantly being introduced, and would be way too much work if there were a lot of values in your data source. In those cases, you may need to go with more traditional labels and be limited to the available fonts. But even that can be a little bit tricky because these are lines, not bars.

For this we need one more calculated field. We only want to label 1 point for each of our bars but we can’t filter out any points. We also can’t use a calculation that results in some null values and some populated values for a given Line Type (because it can inadvertently remove sections of the lines we worked so hard to draw).

Label Name = if [Line Type]=’Outer Lines’ then [Name] END

Now just drag the [Label Name] field to Label and then set the Label options as follows.

You can choose whichever font type and size you prefer, but make sure to set the Alignment to “Top Left’, select “Line Ends” under Marks to Label, and under Options, de-select “Label end of line”. Between the calculated field and these options, only 1 Label will appear per bar, and it will appear to the top left of Point 1 of the “Outer” line (which is the bottom left point in each bar). It should end up looking something like this.

Those are a couple of ways to add Row Labels to your “hand-drawn” bar charts. If you want to add value labels as well you can follow a pretty similar process, but it’s a little trickier. This post is already long enough so I’m not going to go into that, but if you make it this far and want to add value labels, please reach out and I’d be happy to help you. Or you can take the easy way out and do what I did, and just create an image of a “hand-drawn” axis and add it to your dashboard.

Thank you so much for reading, and keep an eye on the blog for more ‘Totally Useless Charts & How to Build Them’!

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