Generation Population

For week 17 of #WOW2021, Sean Miller decided to challenge us with recreating a chart by Nathan Yau (see here for the original). The aim was to recreate within 1 sheet, which I managed to do. So how did I do it? Read on 🙂

  • The groundwork
  • Colouring the bars
  • Adding the year labels
  • Final formatting

The groundwork

The chart itself follows a straight forward structure of multiple blue dimension fields on Columns with a green measure on Rows similar to this view below based on Superstore Sales data – it’s just formatted a bit more creatively!

The data provided just contains 3 fields : SEX, AGE and 2019 Population. We want to present the 2019 Population measure for the Total SEX only by Year. We need to create the Year field, which is simply

Year

2019-[AGE]

I dragged this into the ‘dimensions’ section of the data pane (above the line).

This allows us to create the basic bar chart required

We now need to define the various fields that we will need to add as additional dimensions on the Columns shelf to create the ‘generation’ data panes.

Generation

IF [Year]<= 1927 THEN ‘Greatest
Generation’
ELSEIF [Year]<= 1945 THEN ‘Silent Generation’
ELSEIF [Year]<=1964 THEN ‘Baby Boomer’
ELSEIF [Year] <= 1980 THEN ‘Generation X’
ELSEIF [Year]<=1996 THEN ‘Millennials’
ELSEIF [Year]<=2012 THEN ‘Generation Z’
ELSE ‘Gen
Alpha’
END

NOTE – there is a deliberate carriage return in the condition for ‘Greatest Generation’ and ‘Gen Alpha’ which will force the field to ‘wrap’ when displayed.

Having defined the above, we need to determine

Total Population Per Generation

{FIXED [Generation], [SEX]: SUM([2019 Population])}

and then

% of Total Population

SUM([Total Population Per Generation]) / TOTAL(SUM([Total Population Per Generation]))

NOTE – to create this field, I originally created a ‘quick table calculation’ against the Total Population Per Generation field which I’d displayed on a view, and then dragged the resulting pill into the measures pane to create the new field with the desired calc.

Let’s put these in a table, so we can then check the values, and see that the 2nd and 3rd columns are the same value for each row associated to a particular generation, which is what we need.

Right, so now we need to determine the rank based on the Total Population Per Generation

Rank

RANK_DENSE(SUM([Total Population Per Generation]))

Format this to a custom number with 0 decimal places, but prefixed with #

When added to the table we get

The intention, is that Rank will be displayed as discrete ‘header’ pill rather than a measure, so let’s move Rank to be the 1st pill on the Rows shelf and change to be discrete.

But we need the Total Population Per Generation and % of Total Population fields to be combined into a single pill. So we need to do a bit of string manipulation/ number formatting for this

Total | Percent

STR(ROUND(SUM([Total Population Per Generation])/1000000,1)) + ‘M’ + ‘ | ‘ + STR(ROUND([% of Total Population] * 100,1)) +’%’

This looks complicated, but its because even though you may have applied the relevant display number formatting against the individual numeric measures of Total Population Per Generation and % of Total Population, the formatting is not preserved, when converted into a string field, which this field needs to be. So the relevant calculations need to be applied within the field itself.

This outputs the below

Now we need a way to sort the data so the ‘Greatest Generation’ associated to the earliest years is listed first. I did this by determining the minimum date within each Generation.

Min Year Per Generation

{FIXED [Generation], [SEX]: MIN([Year])}

Add this into the view as the first pill in Rows, and the data should automatically sort from lowest to highest

We can now build the viz – duplicate the table sheet, remove Total Population Per Generation and % of Total Population from the Measure Values section. Drag 2019 Population to Columns, then click the swap rows & columns button :

Colouring the bars

The bars are coloured based on each ‘Generation’ pane. You could hardcode this along the lines of ‘Generation = x OR Generation = y or Generation = z etc’ where x, y and z etc are generations of the same colour. This would return true or false, which you can then add to the colour shelf and adjust accordingly.

I decided to be a bit more dynamic, deciding I wanted to set the colour based on whether it was an odd or even pane.

For this I created another ‘rank’ field based on the field I’d used to ‘sort’ the data, the Min Year Per Generation field.

Sort Position

RANK_DENSE(MIN([Min Year per Generation]),’asc’)

If you add this into the data table, you’ll see each section is numbered 1 -7

From this, we can then determine if the number is even (or not)

Sort Position is even number

[Sort Position]%2=0

Add this onto the Colour shelf which will return True or False and colour accordingly.

Adding the year labels

The year labels are achieved by using a dual axis chart, to plot a point for each specific year (based on the Min Year Per Generation field) at some arbitrary value.

Point to Plot Year Label

IF [Year]=[Min Year per Generation] AND [Year]<>1919 THEN 4700000 END

For each ‘min year’ that isn’t 1919, plot a value at 4.7M.

Add this field to the Rows shelf, change mark type to circle, reduce size to as small as it can, and set the colour transparency to 0.

Add Min Year Per Generation to the Label shelf, then change the alignment to vertical.

Now you make the chart dual axis and synchronise the axis. Some of the colours/marks may change, so reset by removing Measure Names from the Colour shelf and changing the mark types bar to bar & circle.

Final formatting

So at this point all the main components are there. It’s now a case of formatting – removing right and bottom axes, removing gridlines. The vertical dashed lines, are column dividers, set at the pane level only.

The solid left hand axis is set via

The text is formatted using the fonts advised in the requirements and sizes adjusted to suit.

Add on a tooltip, and set the background colour of the worksheet and you should be done.

My published viz is here.

Happy vizzin’! Stay Safe!

Donna

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