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newSchoolWorks.com › VoTechWorks › Technology & Design › Data Science & Analytics › Data Visualization: Principles, Tools, and Storytelling › Lesson 7
TEC-DATA85-06 · Lesson 7 · 14 clock hours · demo

Interactive Visualization in Tableau Public: Core Features

Objective. Students will build an interactive Tableau Public workbook containing three connected worksheets—a bar chart, a map, and a time-series line—with working dimension filters and tooltips using a provided multi-table dataset.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by an industry-certified professional or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

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Interactive Visualization in Tableau Public: Core Features

Tableau Public is a free desktop application that lets you connect to data, build interactive charts and maps, and publish finished workbooks to the web at no cost. Because published workbooks are publicly accessible, you should never upload data that contains personally identifiable information (PII), confidential business records, or any data you are not authorized to share publicly. That is the primary safety rule for this tool: check your data for sensitive content before you publish.

Connecting to Data

Tableau Public can connect to flat files such as CSV and Excel workbooks, and—when used with Tableau Desktop—to live database connections. In this lesson, your instructor will also demonstrate a live connection to a PostgreSQL database so you can see how the workflow differs from a file import. For the CSV path, you open Tableau Public, click Connect > To a File > Text File, and select your CSV. For a database, you click Connect > To a Server, choose your database type, and supply the host, port, database name, and credentials. A live connection queries the database in real time; a data extract copies data locally. For Tableau Public workbooks, data is embedded in the published workbook—another reason to confirm no sensitive fields are included.

Building Relationships Between Tables

When your dataset spans more than one table, Tableau uses relationships rather than traditional joins at the data-source level. Drag both tables onto the canvas in the Data Source tab. Tableau will prompt you to define the linking fields—in this lesson, the county FIPS code links the economic indicators table to the geographic lookup table. Relationships are flexible: Tableau resolves the join context at query time depending on which fields you use in a view, which reduces unintended row duplication compared to a fixed JOIN.

The Three Chart Types You Will Build

Bar Chart with Color Encoding

A bar chart compares discrete categories. Drag a dimension (such as State) to the Columns shelf and a measure (such as Median Household Income) to the Rows shelf. Tableau automatically aggregates the measure. To add color encoding, drag a second dimension—for example, Region—to the Color card on the Marks shelf. Choose a color palette that is accessible to colorblind viewers; Tableau's Color Blind palette is a safe default.

Geographic Map

Tableau recognizes geographic roles. If your field contains county names or FIPS codes, right-click the field, choose Geographic Role, and assign County. Double-clicking a geographic field or dragging it to the view triggers a filled map. Drag your measure to the Color card to create a choropleth map. Always include a title and legend so viewers understand what the shading represents.

Time-Series Line Chart

A line chart shows change over time. Drag a date field to Columns and a measure to Rows. Tableau may aggregate dates by year by default; click the date pill and choose a finer grain (quarter, month) if your data supports it. Use Marks > Line to confirm the mark type.

Adding a Global Dimension Filter

A filter placed on one sheet applies only to that sheet unless you promote it. To create a global filter:

1. Add the dimension (for example, State) to the Filters shelf on any worksheet.

2. Right-click the filter pill and choose Apply to Worksheets > All Using This Data Source.

3. Show the filter control by right-clicking and selecting Show Filter.

Now when a viewer selects a state, all three worksheets update simultaneously—this is the dashboard filter action behavior when sheets share a data source.

Customizing Tooltips

Tooltips appear when a viewer hovers over a mark. Click the Tooltip card on the Marks shelf to open the editor. You can type free text and insert field placeholders using the Insert menu. For this lesson, your tooltip must display at least three fields—for example, County Name, Unemployment Rate, and Year. Keep tooltip text concise; avoid cluttering it with every available field.

Publishing to Tableau Public

When your workbook is ready, go to File > Save to Tableau Public. You will be prompted to sign in to your free Tableau Public account. After saving, the workbook opens in your browser. Click Share to copy the embed link or the direct URL. Submit that URL for grading. Confirm the workbook is set to public visibility in your profile settings—a private workbook cannot be verified by your instructor.

Design Rationale

Every visualization choice is a communication choice. Your one-page rationale should explain: (1) which color palette you selected and why it supports accessibility or the data story, (2) what specific insight each of the three worksheets is intended to reveal for a viewer looking at US county economic data, and (3) any tradeoffs you made (for example, choosing a choropleth over a symbol map). This reflective practice maps directly to skills tested in the Google Data Analytics Certificate and the CompTIA Data+ exam, both of which assess your ability to match a chart type to an analytical question.

Connection to Broader BI Concepts

Tableau's relationship model, filter actions, and tooltip customization have direct parallels in Power BI—the tool covered in the Microsoft PL-300 exam. In Power BI, relationships are defined in the Model view, slicers act as global filters, and report tooltips are customized in the Visualizations pane. Comparing the two tools deepens your understanding of underlying BI principles rather than locking you into one product's vocabulary.

Key terms8

Relationship (Tableau)A flexible link between two tables defined by matching fields; Tableau resolves the effective join at query time based on the fields used in the current view, reducing unintended row duplication.
Mark typeThe geometric symbol Tableau uses to represent data points in a view, such as bar, line, circle, map, or shape; selected on the Marks card.
Choropleth mapA geographic map in which regions are shaded in proportion to a measure value, used to show spatial patterns across areas such as counties or states.
Global dimension filterA filter applied across all worksheets that share a data source, so that a viewer's selection updates every chart in the workbook simultaneously.
TooltipA pop-up text box that appears when a viewer hovers over a mark; it can display any fields from the data source and is customized in the Tooltip card on the Marks shelf.
Live connectionA Tableau data connection that queries the source database in real time rather than storing a local copy of the data; changes in the database are immediately reflected in the view.
Color encodingThe use of color hue, saturation, or lightness to represent a data dimension or measure in a chart, enabling viewers to distinguish categories or gradients at a glance.
Time-series line chartA chart that plots a continuous measure on the vertical axis against time on the horizontal axis, showing trends, cycles, or changes over a period.
In class: Instructor screen-share demonstration of connecting Tableau to a CSV and to a Postgres database (via live connection), creating a relationship between two tables, and building a basic bar chart with color encoding—students observe first, then replicate steps immediately after. · Guided practice using the provided dataset (US county-level economic indicators): students follow a step-by-step lab card to build the bar chart, geographic map, and time-series line, add a global dimension filter, and customize tooltips to show three fields. · Publishing and sharing exercise: students publish the finished workbook to Tableau Public, copy the embed link, and submit it along with a one-page design rationale explaining their color choice and what insight each worksheet is intended to communicate.
Materials: Tableau Public (free desktop app), provided US county economic indicators dataset (multi-table CSV or Postgres connection), Tableau Public account, lab card handout, Tableau official training videos (public.tableau.com/learn/training), Microsoft PL-300 study guide (for comparison of BI tool concepts).
Check: Submitted Tableau Public link and design rationale. Instructor opens link and verifies: all three chart types present, global filter works, tooltips display three fields, workbook is publicly accessible. Pass = all four functional criteria met and rationale submitted.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Data visualization tools and dashboards (Google Data Analytics; CompTIA Data+)
1. A student wants a filter on the State field to update all three worksheets at once. Which Tableau option accomplishes this?
Data governance and ethics (CompTIA Data+; IBM Data Science Professional)
2. Which of the following is the primary data safety rule when publishing a workbook to Tableau Public?
Data modeling and preparation (Microsoft PL-300; IBM Data Science Professional)
3. In Tableau, what is the advantage of using a relationship between two tables instead of a fixed SQL JOIN at the data-source level?
Data visualization tools and dashboards (Google Data Analytics; CompTIA Data+)
4. A student drags a county FIPS code field onto the Tableau canvas and wants it recognized as a geographic field. What is the correct step?
Visualization best practices (Google Data Analytics; CompTIA Data+)
5. Which chart type is best suited to showing how a county's unemployment rate changed from one year to the next across many years?
Data visualization tools and dashboards (Google Data Analytics; Microsoft PL-300)
6. A student's tooltip currently shows only one field. To meet the lab requirement of three fields, the student should:
BI tools comparison (Microsoft PL-300)
7. In the context of the Microsoft PL-300 exam, which Power BI feature most closely parallels a Tableau global dimension filter shown to end users?
Data publishing and sharing (Google Data Analytics; CompTIA Data+)
8. After a student publishes a workbook to Tableau Public, the instructor cannot open the submitted link. What is the most likely cause?
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