Blog

Top 2000 in Perspective – Behind the Scenes

2025-12-30 by Johan de Groot

Every year, the Dutch Radio 2 Top 2000 offers an updated dataset with 2000 songs – and every year, it challenges me to create a completely perspective on it.

The challenge to me isn’t what the data is, but how to see it again with fresh eyes. After 14 years of exploring bar charts, Bézier-inspired snow globes, and long-form dashboards, this year I opted for a 3D grid.

This post looks behind the scenes of that process: the design choices, technical constraints, and small visual tricks that shaped this year’s visualization. For the TL;DR people: the interactive dashboard can be found here.

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How to Visualize High-Value Metrics in Tableau Without Starting at Zero

2025-11-29 by Johan de Groot

Every time you publish a chart that doesn’t start at zero, someone will appear in the comments accusing you of misleading your audience. But the truth is simple: not every dataset lives anywhere near zero.

When working with high-value metrics – like atmospheric pressure, energy usage, or financial KPIs – starting a chart at zero often flattens the trend and hides important variation. Simply removing zero can help, but it can also exaggerate small fluctuations, making lines appear more dramatic than they really are. In this guide, I’ll show how to visualize high-baseline data in Tableau using dynamic axis adjustments, reference lines, and buffer zones to create accurate, readable, and visually balanced charts.

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Why is COUNTD so slow – and how can I fix this?

2025-11-16 by Johan de Groot

When you start tuning a Tableau dashboard or SQL query for performance, one thing jumps out quickly: COUNTD can slow things down.

The count-distinct is an extremely useful function which looks simple on the surface, but under the hood it forces the engine to do extra work that adds up fast. Understanding why this happens – and what alternatives you can use – makes a big difference in keeping your dashboards responsive.

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Visualizing ‘Dynamic’ Data using a Sine Wave

2025-10-25 by Johan de Groot

Recently I ran into a small but surprisingly tricky problem: how do you visualize something that’s in progress? A standard bar chart works usually perfectly for completed values, but what about the final bar isn’t finished yet because e.g. the year isn’t finished yet,

Fading it out, changing the shape or adding a label like “in progress” didn’t feel right. I wanted something that instantly communicates “this is still ongoing”.

Inspired by how Spotify shows an ongoing song I started experimenting with using a sine wave to bring that bar alive. Instead of a static column, the last bar gently oscillates – hinting that it’s active, not finished.

In this post, I’ll walk through how to create this effect in Tableau step by step.
If you don’t need an ‘in progress’ viz, you can always use it for something else….

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Add ‘All’ and more options to a Dynamic Parameter

2025-09-18 by Johan de Groot

A couple of years ago, Tableau introduced one of its most highly requested features ever: Dynamic Parameters. This feature made it possible to populate a parameter with values directly from a data source, rather than being limited to static, manually entered values.

This works great, but as soon as this was available a new request came up: adding manual values to the list – especially the ‘All’ value.

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