Day 2 was… an interesting one, in a lot of ways.

The main challenge was using a tool similar to tableau, called Power BI, to create meaningful visualizations. I wanted to use this chance to talk about some of the pros and cons with Power BI, specifically from a comparison standpoint to Tableau.

Visuals and Charts

Power BI has a lot of unique visualization skills. Power BI is designed to be modular – for people to be able to code their own visualization types into it freely. Want a chart with each bubble showing it’s place on axis at a moving point in time? Want a chart showing networking? Anything’s possible – up to and including turning your data points into fish and having them swim around in a small aquarium. These custom visuals are generally created as free products by Power BI users, that are then distributed online, so there’s a massive list available to anyone who wants to use them.

However, that can also create problems. Tableau’s visuals may not be as varied, but they’re very easy to manipulate and coordinate. All of Tableau’s visuals operate with very similar underlying frameworks, so formatting them is incredibly easy. With Power BI, you have no such guarantee – most charts are less flexible in formatting than their Tableau equivalents, and the custom versions are likely to miss even more customization options. An example of which is above – the reason that the axes look so greyed out is because there is just no way to colour them any brighter. Perhaps the most damning absence is the lack of sequential colouring – you can’t colour by a measure, only by category. If the type of chart you’re using has every other detail accounted for, you can’t use colour as you could in Tableau.

In essence, Power BI is a modular program with fixed chart designs. Tableau is a fixed program with modular chart design. And while it may seem small, it makes a lot of difference.

One Screen, Two Problems

From the moment you start creating a visualization in Power BI, it’s part of a dashboard. There isn’t a separate view for editing the sheets and their combined state – only one for viewing both.

This has it’s advantages and disadvantages. For one, having every setting that you might need available to you at once is undeniably handy. Creating visualizations in a Tableau worksheet can come with unrealistic expectations – for example, that your densely-packed map of points will still make sense in the small area it actually has to fit. Working in Power Bi lets you more easily see the final product as it’s being made, and catch problems like that before they happen.

But two sets of settings on one page means that there are less customization options overall. Focusing just on the worksheet means there are whole Tableau features – like the analytics pane – that just aren’t part of Power BI’s charts. Tableau allows you to go further in depth on any vis than Power BI ever could. And the deeper into data analytics that I go, the more I find that matters – the more I find myself leaning on hundreds of little formatting advantages.

Conclusion

Power Bi is an interesting tool – one with arguably more potential that Tableau, but it’s wings clipped by the very nature of user-run modules. In some situations, Power Bi is the undisputed king – in others, it doesn’t stand a chance.

One of the most crippling in that regard is the loss of Sequential Colouring. That is a whole dimension of visual data that is clipped in it’s functionality – and it’s one that deeply affects your ability to present the data in an appealing way.

In the end, though, neither product completely supplants the other. They both have advantages and disadvantages, and it comes down to the user to decide which one they want to use. Is it better to use Power BI, or Tableau? I lean towards the latter, but then, I’m trained in that tool. The

David Ruhnau
Author: David Ruhnau