Power BI Course
Visualization Basics
Choosing the wrong chart type is one of the most common ways to make correct data tell the wrong story. This lesson covers the principles behind picking the right visual, walks through every core chart type in Power BI, and explains how to format visuals consistently so your reports look intentional rather than assembled by accident.
The One Rule of Chart Selection
Every chart type answers a specific kind of question. Before you pick a visual, ask yourself what question this chart is answering. The answer determines the chart type. Using the wrong chart for the question does not just look bad — it actively misleads the viewer by implying a relationship in the data that does not exist.
| The question you are answering | Use this chart type | Do NOT use |
|---|---|---|
| How do categories compare to each other? | Bar / Column chart | Pie chart (hard to compare slices) |
| How does a value change over time? | Line chart | Bar chart (implies discrete, not continuous) |
| What share does each category contribute? | Donut / Pie chart (max 5 slices) | Line chart (implies time progression) |
| What is a single headline number? | Card / KPI visual | Bar chart with one bar |
| Is there a relationship between two numeric values? | Scatter chart | Line chart (implies time) |
| How do sub-categories contribute to a total? | Stacked bar / Stacked column | Multiple pie charts |
| Where does performance sit vs a target? | KPI visual / Gauge | Plain card (shows no target) |
The Core Visual Types — One by One
Power BI ships with over 30 visual types. Most professional reports use fewer than ten. These are the ones you need to know thoroughly — every other visual is a variation on these foundations.
Formatting Visuals — The Format Pane
Every visual has a Format pane — the paintbrush icon in the Visualizations panel. Click any visual, then click the paintbrush icon to open it. The Format pane is divided into two tabs: Visual (settings specific to this chart type) and General (settings common to every visual — title, background, border, shadow, alt text).
Applying Format Consistently — The Format Painter
Once you have formatted one visual exactly how you want it — title style, data labels, background, colours — you can copy that formatting to any other visual in one click using the Format Painter. This is the fastest way to ensure consistent formatting across an entire page without manually repeating every setting.
Using the Format Painter:
1. Click the source visual (the one with the formatting you want to copy)
2. In the Home ribbon, click the Format Painter icon (paint roller icon)
The cursor changes to a paint roller
3. Click any other visual on the canvas
All formatting from the source visual is instantly applied
To apply to multiple visuals without re-clicking Format Painter:
Double-click the Format Painter icon (step 2) to lock it on
Then click each destination visual one by one
Press Escape when done
What IS copied:
Title font, size, colour · Background colour · Border settings
Data label settings · Axis font sizes · Legend position
What is NOT copied:
Field assignments · Visual type · Data itself
Specific colour mappings tied to data values
Conditional Formatting
Conditional formatting applies colour, icons, or data bars to cells in a table or matrix automatically based on the value. It turns a flat table into a heatmap that lets viewers instantly spot high and low performers without reading every number.
| Region | Orders | Revenue | Revenue (data bar) |
|---|---|---|---|
| North | 412 | $38,200 | |
| South | 287 | $24,100 | |
| East | 198 | $13,450 | |
| West | 89 | $7,700 |
To apply conditional formatting: select the table or matrix → click the field dropdown arrow next to the measure in the Values well → Conditional formatting → choose Background colour, Font colour, Data bars, or Icons.
Teacher's Note: The most common formatting mistake beginners make is treating the Format pane like a toy — adding shadows, 3D effects, gradients, and eight different colours because they can. Professional reports use restraint: one or two brand colours, consistent typography at two sizes (title and body), minimal borders, and no decorative elements that do not carry information. The goal of formatting is to reduce visual noise so the data speaks louder — not to make the chart look busy.
Practice
Practice 1 of 3
You want to show how Revenue has changed month by month over a full year. The correct chart type to use is a ___ chart, because it shows continuous change over time.
Practice 2 of 3
To copy the title style, background colour, and data label settings from one visual to another without manually re-entering every setting, you use the ___ Painter in the Home ribbon.
Practice 3 of 3
The KPI visual requires three field wells — Value (the actual metric), Target (the goal), and Trend ___ (a date field that draws the mini sparkline showing recent history).
Lesson Quiz
Quiz 1 of 3
A colleague builds a line chart showing Revenue by Region (North, South, East, West). The chart has four points connected by a line. Why is this the wrong chart type for this data?
Quiz 2 of 3
You have a table visual showing Revenue by Region. You want to make the highest revenue cells green and the lowest red without adding any extra columns. What is the correct approach?
Quiz 3 of 3
You format a bar chart with a specific title font, background colour, and data label style. You now need to apply the same formatting to seven other bar charts on the page. What is the most efficient method?
Next up — Lesson 15 covers Basic Charts in depth — building and fine-tuning the clustered bar, clustered column, line, area, and combo charts with real datasets, sorting, Top N filtering, and secondary axes.