I have already covered Tableau in another post. This time I am going to run through how to colour the different quadrants of a scatter plot (or graph). This was part of a presentation by Tableau’s Sophie Sparkes at BCU.
The data used was UK Performance Indicators 2015/16: Non-continuation rates produced by HESA.
I used the student edition of Desktop Tableau version 10.2.
Step one – obtain and clean the data
After downloading the data it needed to be checked to see if it needed to be cleaned in any way. The download contained many tables, but we were working with Table 3a.
**only work on a copy of the original data, never work on the original**
Part of the cleaning/checking is to look at the header/footer information to see how useful it is.
From the above image you can see that the table included totals as well as the individual university data. These totals needed to be removed, so that only data for the individual universities is used.
The method shown was to group the rows containing totals.
After selecting the rows you don’t want (as seen above) click on GROUP. A new entry will appear in the dialogue box, which will have a paperclip symbol. Click on that and then on RENAME.
Use something simple to remind you of the group’s contents – I used ‘Totals’
Then tick the ‘OTHER’ box and then on OK.
How to filter the unwanted group from your data
Click OK and you will be taken back to the table. You will notice that the rows with a total have been removed.
Creating the scatter plot
Click on SHEET 1 down at the bottom left of Tableau’s screen. This will take you the graph plotting part of the software. A wizard will be on the right-hand side. It shows what data is required for each type of graph.
We are looking at the percentage of mature and young students that drop out of university. So one measure goes into the columns and the other goes into the rows. It doesn’t matter which way round.
However, if this is all we do then all we’d get is one circle. The university names need to be added as well.
‘Table 3a – Non-continuation following year of entry: UK domiciled full-time first degree entrants 2013/14 HE provider’ goes into the MARKS box.
Click on the NULLS and select SHOW DATA AT DEFAULT POSITION until all the null indication has been removed.
Now the graph needs to be divided into quadrants. This is done clicking on the ANALYTICS folder (top left-hand corner) and dragging the AVERAGE LINE button across to the graph.
A window will pop up (ADD A REFERENCE LINE). Depending on when you release the button an average line can be applied to either or both axis.
The shape of the plots can be changed by clicking on the SHAPE button in the MARKS area.
Colouring each quadrant
Highlight a quadrant by left clicking in the area and dragging the mouse until the whole quadrant is highlighted.
Click on CREATE SET and then click OK. Repeat for the remaining quadrants (remember to click anywhere on the graph before highlighting the next quadrant to ensure that the average lines are in the correct place). Select the DATA tab and there should be four sets listed at the bottom.
Drag all the sets to the MARKS box. Each set has a DETAIL icon to its left. Click on one and select COLOR. Then click on the COLOR button and select EDIT COLORS.
To select a colour for a quadrant click on a DATA item in the left hand window. Each quadrant has one IN and three OUTS, so only adjust the colours for DATA items with only one ‘IN’. If the first three colours you use are different to the default colour you only need to do this three times.
Four different colours – nearly done
You now have different colors for each quadrant (as long as you didn’t decide to use a colour more than once!!).
Now the title needs to be updated.
The scatter plot is now finished and is ready to add to a dashboard or to be shared.