Tableau Course
The Visual Shelf
Every chart in Tableau is built by placing fields onto shelves — and understanding how each shelf works gives you complete control over what your visualisation looks like before you drag a single field.
The Shelf System
Tableau's worksheet has a set of named shelves — dedicated drop zones that each control a specific aspect of the chart. Think of each shelf as a channel: whatever field you place on it gets encoded in a particular visual way. The five shelves you will use in every lesson are Columns, Rows, Filters, Pages, and the Marks card properties.
Controls the horizontal axis. A Dimension on Columns creates column headers across the top. A Measure on Columns creates a horizontal axis with a numeric scale. You can place multiple fields on Columns to create side-by-side panels.
Controls the vertical axis. A Dimension on Rows creates row headers down the left. A Measure on Rows creates a vertical axis with a numeric scale. Adding more fields to Rows stacks charts vertically into separate panes.
Restricts which data is included in the view. Dropping a field here does not add it to the chart visually — it just limits the rows of data that feed into the chart. You can filter by value, condition, or date range.
Splits the view into separate pages — one per value of the field. Useful for animated walkthroughs by year or category. Less commonly used than the other shelves but powerful for presentations.
The Marks Card — Visual Encoding Properties
The Marks card is not a single shelf — it is a collection of encoding channels. Each channel controls one visual property of the marks drawn in the view. Dropping a field onto a Marks channel encodes that field visually without adding it to an axis.
The Mark Type Selector
At the top of the Marks card is a dropdown that lets you choose the mark type — the shape Tableau uses to represent each data point. Tableau picks a sensible default based on what fields you have placed, but you can override it at any time.
| Mark Type | Tableau Uses It For | Typical Scenario |
|---|---|---|
| Bar | One bar per category, height = measure value | Sales by Category, Revenue by Region |
| Line | Points connected in sequence, usually by date | Monthly Sales trend, daily website visits |
| Circle / Shape | One dot per data point | Scatter plots, individual order views |
| Text | Renders the label value directly in the view | Cross-tab text tables, highlight tables |
| Area | Filled area below a line | Cumulative trends, stacked area charts |
| Map | Auto-selected when geographic fields are used | Sales by State, customers by Country |
| Automatic | Tableau chooses the mark type based on field types | Default for new worksheets — let Tableau decide first |
Building a Chart — The Shelf Interaction in Practice
Here is a step-by-step example of building a bar chart of Sales by Region using the Superstore data — showing exactly which shelf each field goes onto and what the view looks like at each step:
A Fully Built Shelf Layout — Mockup
Here is what the worksheet looks like after completing the four steps above:
Multiple Fields on the Same Shelf
You are not limited to one field per shelf. Placing multiple fields on Columns or Rows produces nested or panelled layouts that let you compare data at multiple levels of detail simultaneously.
Creates a nested column structure — Sub-Category headers appear inside each Category group. Produces a detailed breakdown without needing filters.
Creates two separate chart panes stacked vertically — one for Sales and one for Profit — both sharing the same Columns axis. Ideal for comparing two metrics side by side.
When a chart looks wrong, the shelf is almost always the reason. The two most common mistakes are placing a Measure where a Dimension belongs (getting a single aggregated bar instead of multiple bars) and placing a field on the wrong axis (chart is sideways). Before adjusting anything else, check each shelf: does every field on Columns and Rows make sense for what you are trying to show? A quick drag from one shelf to another is usually all it takes to fix the view.
Practice Questions
1. Which shelf restricts the rows of data shown in a view without adding any visual element to the chart?
2. Dragging a Dimension onto which Marks card channel splits the bars in a bar chart into colour-coded segments?
3. Which shelf splits a Tableau view into separate pages — one per value of the field placed on it?
Quiz
1. What does placing two Measures on the Rows shelf produce in the Tableau view?
2. What is the purpose of dropping a field onto the Tooltip channel of the Marks card?
3. Which mark type does Tableau use when you place a Dimension on Columns and a Measure on Rows by default?
Next up — Lesson 8: Building basic charts in Tableau — bar charts, line charts, and pie charts built step by step from the Superstore dataset.