The #SWDChallenge this month was a graph makeover - simply turn any existing graph into a better one.
Something I do for fun (acknowledgment of my data viz obsession!) is collect graphs I think could be presented better differently.
The graph I picked for this challenge is one on my local council’s website. It shows how Wellington City Council allocate rate payments across their service areas.
Before: graph to makeover
Source: Wellington City Council website
Here were some of my initial comments:
What do the colours mean? Is green conservation?
Radial bar - is it a pie, is it a bar? 🤔
The bars are hard to compare.
Per $100 isn’t that relatable as rate payments are much higher than this (I realise this could also be read as percent though).
There is no order to the bar arrangement, apart from colour (but no legend to identify what this represents).
The big icon circles make the bar length deceiving.
I felt I needed to understand the topic more so poked around the Council website and followed up with a few questions (thank you, Heather for replying to my seemingly random tweets!).
I want to emphasise the resulting visualisation is in no way a reflection of WCC endorsement. I have personally made over their graph for learning/demonstrative purposes.
Here are the changes I made, and my reasoning behind them:
Lose the overall circle.
Radial bar graphs make it very hard to compare variables. Anyone using this type of graph should try to apply some order to the positioning of the bars e.g. to reflect value or time etc.
Lose the icons.
Icons are great to increase engagement of a data visualisation but too many can add clutter to a piece. These circular icons also deceivingly add to the area of each bar.
Group the bars.
For me there are too many bars at the same level of visual hieracy. My brain desperately wants to apply more Gestalt principles to create some order.
I’ve used the priority areas below (detailed on another page of the Council website) to help categorise the bars:
The priority area colour scheme has also been applied where possible. Anything not covered by these categories I’ve grouped into General Council Operations. Disclaimer: I’m not sure if the Council would find this correct!
Rank the bars.
Ranking bars from highest to lowest removes some of the cognitive load on the viewer and helps increase the visual order of the graph.
Make the dollars more relatable.
Anyone who pays rates knows the amount is likely to be a lot more than $100. Instead of using a ‘per $100 of total rates’ measurement I’ve gone with the average rate payment. It’s still only an average, but a more relatable figure with less calculation required by the viewer.
Add in Goods and Services Tax.
From the perspective of the rate payer, their total payment (including tax) is the amount they pay in rates. If you’re showing the true allocation of a rate payment I think GST should be included.
After: graph made over
I've kept a lot of WCC branding elements but added more alignment, grouping and a different view of the data.
If you're looking for a way to improve your data viz skills, I think makeovers are a great way to do this. Sometimes just listing out the elements you think don't work (and why!) is a quick and easy way to train your design eye.
Thanks, Wellington City Council for starting off this data viz 💛🖤
Response from Wellington City Council: