Overview
This lecture introduces Tableau, focusing on how to import Excel data and familiarize yourself with Tableau's user interface for beginner data visualization tasks.
Opening Tableau and Importing Data
- Upon starting Tableau, you see a home screen with data source options.
- Tableau supports importing from Excel, text files (CSV), JSON, PDF, Access (Windows only), and many others.
- The example uses Tableau's pre-configured "Coffee Store" Excel file.
- To import, click "Microsoft Excel," select the file, and wait for Tableau to load it.
Understanding Data Structure After Import
- Excel files have worksheets (tabs); select and drag the relevant table to Tableau's canvas.
- Tableau automatically detects data types: numbers (hash sign), geographic info (globe), dates (calendar), and strings (ABC).
- Geographic data such as area codes can be visualized on maps.
- Sometimes Tableau may misclassify data types; you can manually change them by clicking the type icon.
- Example: If "budget profit" should not be numerical, change its type from the menu.
Interface Tour: Main Tableau Workspace
- After importing, click "Sheet 1" to access main workspace.
- Tableau divides imported fields into "dimensions" (blue pills) and "measures" (green pills).
- Dimensions: Non-numeric, categorical fields (e.g., names, product IDs, dates, geographic info).
- Measures: Numeric fields suitable for calculations.
- Tableau auto-generates fields like "count" (row count) and adds latitude/longitude for geographic data.
- The center canvas is used to build visualizations.
- The Marks card lets you add details, color, size, text, and tooltips to visualizations.
- Visualization types (bar, line, map, etc.) are selectable from a dropdown.
- Filters pane lets you restrict data (e.g., by area code).
- Shelves for columns and rows help structure visualizations.
- "Show Me" suggests visualization types based on selected data.
- Tabs at the bottom let you add new sheets, dashboards, or stories.
Key Terms & Definitions
- Dimension — Non-numeric data in Tableau, used for categorization (blue pill).
- Measure — Numeric data in Tableau, used for calculations (green pill).
- Marks Card — Interface area for customizing visual details like color, size, and labels.
- Canvas — Main area where visualizations are built.
- Sheet — A workspace for one visualization or analysis in Tableau.
- Dashboard — A Tableau feature combining multiple sheets into a single view.
- Story — Sequence of visualizations for presentation, similar to slides.
Action Items / Next Steps
- Practice importing the Coffee Store Excel file into Tableau.
- Familiarize yourself with identifying and changing data types in Tableau.
- Explore the interface: dimensions vs. measures, marks card, filters, and visualization options.
- Prepare for the upcoming exercise using this imported data.