Dataviz Universe

👋 Hi! I’m currently teaching data visualization with R and Python to over 1,000 people, and I absolutely love it! ❤️ Each course includes a Discord channel where students share their charts and get constructive feedback. A common struggle Here’s something I’ve noticed: most students are great at coding, creative, and know the dataviz best practices.But many still struggle with design. They produce charts that are technically correct but not very pleasant to look at.So what really makes the...

👋 Hi! While working on my ggplot2 uncharted project this week, I revisited many old posts from the R Graph Gallery. It reminded me of a classic issue in data visualization, and how to fix it. It probably happened to you already. It can lead to misleading conclusions. In the worst cases, it can make a chart completely unreadable. The good news is: the fix is easy once you know it. So you won't need to worry about the FBI knocking on your door for producing a bad chart next time you face the...

👋 Hi! First, a quick apology for missing last week's email. 😔 It’s the first time this year I’ve skipped one, but with over 450 people joining the launch of ggplot2 uncharted, things got a little intense on my end. Anyway, let's go back to our usual, short & actionnable dataviz tip with a few words about bubble size. 🫧 Why bubbles? Circles are everywhere in dataviz. In scatterplots, their position usually encodes two variables (x and y). But sometimes, we also use their size to encode a...

👋 Hi! I hope you’re doing well on your side of the planet. Here, spring is finally peeking through. I’m writing this from a hammock, with a lazy cat napping beside me and my kid playing with flowers. Love it! ❤️ Anyway, you’re not here for daydreaming but to sharpen your dataviz skills, so let's get into it. Good chart !== bad chart I’ve been building charts and teaching dataviz for a while now, and one thing always strikes me: the same common mistakes pop up over and over. Some of them are...

👋 Hi! I know, it’s not Saturday today 🙈.But this week is special to me because I’m launching my latest project!! Can I tell you the story? I love R About 13 years ago, I finished my master's degree in genetics and started working as a bioinformatician. I discovered the joy of data analysis and fell in love with the final step: building great charts. To document what I learned, I created the R Graph Gallery, a collection of chart examples with code and explanations. Examples are sorted by...

👋 Hi! As you might know I try to share a little dataviz tips & inspiration on LinkedIn every day.And this week, one post really struck a chord: The Graph This map is a choropleth map. It shows the unemployment rate in Belgium. Originally created by Koen Van den Eeckhout in Tableau, my associate Joseph (co-teacher for our Matplotlib Journey course) recreated it in Python.Here is a glimpse of his iterative process. We like calling this an "Evolution of a Matplotlib". 🔗 Check out the code here!...

👋 Hi there! As a software engineer and educator, I spend a lot of time watching beginners write code. And one thing always stands out: how slow it can be. Not because of logic or bugs, but because of typing & formatting! So today I suggest we talk about formatters.Before we start, can you answer this tiny poll? You already use a formatter when you code: TRUE FALSE If you're not using one yet, it’s an easy win that will instantly boost your productivity. And if you already are, read on:...

👋 Hi! Hope things are going great on your side of the world. Over here, life is pretty sweet: I'm writing this while sipping mint tea in Morocco, where my brother is getting married! ☀️🎉 Anyway, today I want to share something I love about the dataviz world: It's 2025, and somehow... We’re still inventing new chart types!Let me show you in just a few minutes as usual. 🤯 The trouble with stacking Stacked bar & area charts are everywhere. But they have a problem: they make it really hard to...

👋 Hi! Today’s the final step in my How the Web Works series! We started by exploring what HTML, CSS, and JavaScript are. Then we saw how to use these tools to create interactive graphs, even when working with R or Python. Finally, I showed how to host your work on GitHub Pages, turning it into a free mini-website. 🔥 Today, I want to tackle a tricky but crucial concept: ⚡️ Static vs Dynamic websites A static website is like the one we built last week. You write a simple HTML file (manually, or...

👋 Hi there! Welcome to step #3 of my series on the essentials of the web for dataviz practicioners. In step 1, we learned that a website is essentially an HTML file with a bit of CSS and JS. In step 2, we discovered that the libraries you use in R and Python to create interactive graphs are just wrappers that generate the HTML for you. You're almost a web developer now! With tools like Quarto and Jupyter, you can embed those interactive charts in stunning HTML reports. Now, the question is:...