TechnologyThe StorytellerIntermediate
Data Visualization in Practice, a free technology course on Tomo

Data Visualization in Practice

Transform raw numbers into clear, honest, and compelling visual explanations. Learn the mechanics of visual perception, high-density layouts, functional color palettes, and ethical chart design.

Like Duolingo, but for Data Visualization in Practice. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.

18 levels across 3 sections, about 36 minutes end to end, roughly 7 days at five minutes a day. It moves through Making Visuals Work Fast; Handling Density and Uncertainty; and Perception, Color, and Ethics. It assumes you already know the basics.

18 bite-size levelsAbout 5 minutes each

Free forever · No credit card · iPhone & Android

Chroma the Chameleon, the guide who teaches the Data Visualization in Practice course
Data Visualization in Practice
with Chroma the Chameleon
18
Levels
3
Sections
5
Min/day
What you'll learn

Key ideas in Data Visualization in Practice

  • Extraneous ink like drop shadows and 3D effects distorts perception without adding data.
  • Heavy grid lines compete with data marks instead of subtly assisting eye alignment.
  • Stripping non-data ink lets readers process core data variations with less cognitive load.
  • Separate legends force split-attention shifts back and forth across the chart area.
  • End-of-line direct labels let readers identify series identity in the same fixation as the final value.
  • Direct labeling removes color-matching ambiguity when two series share similar hues.
  • Muting non-target data series in gray preserves comparison context without fighting for attention.
  • Reserving high-saturation color for a single series immediately pulls preattentive visual focus.
  • Using multiple saturated colors simultaneously destroys hierarchy and creates visual competition.
  • Sorting categorical bars by value reveals highest, lowest, and rank order in a single glance.
  • Alphabetical sorting scrambles bar lengths into visual noise, forcing manual eye-scanning.
  • Lookup utility rarely justifies sacrificing the immediate comprehension of ranking patterns.
  • Action titles declare the primary analytical insight rather than merely listing variables.
  • Descriptive variable headers make viewers perform analytical work to deduce the point.
  • Pairing an active takeaway headline with technical metrics in a subtitle anchors clarity quickly.
  • Position along a common aligned scale yields the lowest error rate in visual judgment.
Why not just Google it

You've tried the other tabs

Wikipedia

Thirty open tabs. Four facts you actually kept.

YouTube

You watched. You nodded. By Sunday it was gone.

ChatGPT

One answer, then back to scrolling.

Online courses

Eight weeks. You meant to finish. You didn't.

Tomo gives Data Visualization in Practice the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.

Try a question

Here's what playing it feels like

A real question from this course. Take your best guess.

Stripping the Visual Clutter

Imagine looking at a chart where thick, dark grid lines crisscross behind the bars. What story problem does this create?

Get it right to open this lesson and 17 more in the app.

Course map

Where Data Visualization in Practice takes you

  1. 1

    Making Visuals Work Fast

    • Stripping Visual Noise for Immediate Clarity
    • Selecting Encodings by Perceptual Accuracy
  2. 2

    Handling Density and Uncertainty

    • Resolving Overplotting in Dense Datasets
    • Visualizing Distributions Beyond the Mean
  3. 3

    Perception, Color, and Ethics

    • Functional Color Choices for Data
    • Framing Data Without Deception

3 sections · 6 units · 18 levels. Built to play, not to enroll.

How it's taught

You pick the voice

This course
The Storyteller

Data Visualization in Practice is taught in the The Storyteller style: every lesson is a story. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.

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