# Sankey, chord, radar, tile maps and densification

*Tableau Consultant Study Guide · Design and Troubleshoot Calculations and Workbooks · Last updated November 3, 2026 · https://www.certifyforce.com/study-guide/tableau-consultant/design-and-troubleshoot-calculations-and-workbooks/sankey-chord-radar-tile-maps-and-densification*

Match an advanced chart to the question it answers (flows, pairwise interactions, multi-variable profiles, equal-weight geography, many small trends), know when a simpler chart wins, deploy Viz Extensions on Tableau 2024.2 and later, and densify a view so calculations work on generated marks.

- Certification: Salesforce Tableau Consultant
- Exam section: Design and Troubleshoot Calculations and Workbooks
- Study guide: https://www.certifyforce.com/study-guide/tableau-consultant

**Official exam objective:**

> Recommend when to use an advanced chart type, such as Sankey, chord, radar, tile map, small multiples, and data densification.

## What the exam expects

- Recommend a Sankey, chord or radar chart from the shape of the question (transitions between states, interactions between pairs of entities, a profile across several measures), and recognize when a simpler chart serves the data or audience better.
- Recommend a tile grid map for equal-weight geography and small multiples for many side-by-side trends.
- Explain how Viz Extensions (Tableau 2024.2 and later) are added, encoded and allowed to run on Tableau Server or Tableau Cloud.
- Use data densification (Show Missing Values plus Infer Properties from Missing Values) so calculations return values on generated marks.

Key terms:
- **Viz Extension:** a web application added from the Marks card that renders a custom chart type on a worksheet.
- **Level and Link:** the Sankey extension's own encodings for the categories it relates and the measure that sizes each flow.
- **Tile grid map:** a map drawn as a grid of identical tiles, one per geographic unit.
- **Small multiples:** any view that is a grid of individual charts, one per pane.
- **Data densification:** marks generated by Tableau that no underlying record supports.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Viz Extensions release | Available since Tableau 2024.2, from the Marks card | [Your Guide to Viz Extensions](https://www.tableau.com/blog/your-guide-tableau-viz-extensions) |
| Sankey Level encoding | Up to 5 discrete dimensions | [Add Viz Extensions](https://help.tableau.com/current/pro/desktop/en-us/viz_extensions.htm) |
| Sankey Link encoding | Sizes each link's width from a numeric measure | [Add Viz Extensions](https://help.tableau.com/current/pro/desktop/en-us/viz_extensions.htm) |
| Network-enabled extensions | Blocked until on the site safe list | [Manage Dashboard and Viz Extensions](https://help.tableau.com/current/server-linux/en-us/dashboard_extensions_server.htm) |
| Published extension data access | Workbook or view must allow Download Summary Data | [Add Viz Extensions](https://help.tableau.com/current/pro/desktop/en-us/viz_extensions.htm) |
| 2023 Tableau Public pilot | Ended June 30, 2023; its charts were removed | [Exploring Sankey and Radial Charts](https://www.tableau.com/blog/exploring-sankey-and-radial-charts-new-chart-types-pilot-tableau-public) |
| Infer Properties from Missing Values | Off by default; requires Show Missing Values | [Generated Marks](https://help.tableau.com/current/pro/desktop/en-us/predictions_generated_marks.htm) |
| Show Missing Values | Only for a defined domain such as dates or numeric bins | [Show or Hide Missing Values](https://help.tableau.com/current/pro/desktop/en-us/missing_values.htm) |

## Check yourself

- Why can't Show Missing Values fill the gaps in a field that lists colors?
- When would a 100% stacked bar beat a sunburst?
- Does ZN add zero rows for months that have no records at all?
- How does a Viz Extension differ from a dashboard extension in where it is added?
- Which extensions run on a site without a safe-list entry once extensions are enabled?

## Sources

- [Add Viz Extensions to Your Worksheet](https://help.tableau.com/current/pro/desktop/en-us/viz_extensions.htm)
- [Your Guide to Tableau Viz Extensions](https://www.tableau.com/blog/your-guide-tableau-viz-extensions)
- [Exploring Sankey and Radial Charts with the New Chart Types Pilot on Tableau Public](https://www.tableau.com/blog/exploring-sankey-and-radial-charts-new-chart-types-pilot-tableau-public)
- [How to Make Tile Grid Maps in Tableau](https://www.tableau.com/blog/how-make-tiled-maps-tableau-45742)
- [Build a Basic View to Explore Your Data](https://help.tableau.com/current/pro/desktop/en-us/getstarted_buildmanual_ex1basic.htm)
- [Predictive Modeling with Generated Marks](https://help.tableau.com/current/pro/desktop/en-us/predictions_generated_marks.htm)
- [Show or Hide Missing Values or Empty Rows and Columns](https://help.tableau.com/current/pro/desktop/en-us/missing_values.htm)
- [Manage Dashboard and Viz Extensions in Tableau Server](https://help.tableau.com/current/server-linux/en-us/dashboard_extensions_server.htm)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 9 linked practice questions, and unlimited timed mock exams are included with the Tableau Consultant pack (USD $19): https://www.certifyforce.com/practice-exams