Creating choropleth maps
by Matt Floyd, Ashley Ohmann, Ashutosh Nandeshwar, Jen Stirrup
Tableau: Creating Interactive Data Visualizations
- Tableau: Creating Interactive Data Visualizations
- Table of Contents
- Tableau: Creating Interactive Data Visualizations
- Tableau: Creating Interactive Data Visualizations
- Credits
- Preface
- 1. Module 1
- 1. A Short Dash to Dashboarding!
- 2. Summarizing Your Data for Dashboards
- 3. Interacting with Data for Dashboards
- 4. Using Dashboards to Get Results
- 5. Putting the Dash into Dashboards
- 6. Making Dashboards Relevant
- 7. Visual Best Practices
- 2. Module 2
- 1. Connecting to Data Sources
- Introduction
- Connecting to text files
- Connecting to Excel files
- Connecting to Access databases
- Connecting to a SQL Server
- Pasting from a clipboard
- Connecting to other databases
- Connecting to Windows Azure Marketplace
- Understanding dimensions and measures
- Changing data types
- Applying filters
- Merging multiple data sources
- 2. Creating Univariate Charts
- 3. Creating Bivariate Charts
- 4. Creating Multivariate Charts
- 5. Creating Maps
- 6. Calculating User-defined Fields
- 7. Customizing and Saving
- 8. Exporting and Sharing
- 9. Exploring Advanced Features
- 1. Connecting to Data Sources
- 3. Module 3
- 1. Getting Started with Tableau Public
- 2. Tableau Public Interface Features
- 3. Connecting to Data
- 4. Visualization – Tips and Types
- 5. Calculations
- 6. Level of Detail and Table Calculations
- 7. Dashboard Design and Styling
- 8. Filters and Actions
- 9. Publishing Your Work
- A. Bibliography
- Index
A choropleth map, known as a filled map in Tableau, is a modification of a traditional marks map, in that study areas (regions, states, and counties) are filled with the measure of interest and colors are used with different hues or diverging progression to assist the reader in identifying areas of poor or good performance.
Let's use the sample file, Sample – Superstore Sales (Excel). Open a new worksheet and select Sample – Superstore Sales (Excel) as the data source.
Once the data is loaded on the worksheet, perform the following steps to create a choropleth or a filled map:
- Click on the Show Me button to bring the Show Me toolbar on the screen.
- While holding the Ctrl key, click on Profit from Measures and State from Dimensions.
- Click on filled maps on the Show Me toolbar to create a choropleth map as shown in the following screenshot:
We selected State as the level of detail for this example of choropleth maps (known as filled maps in Tableau), and Tableau created a color range to encode Profit; that is, dark green for higher profit and pink for losses. This allows the reader to quickly identify Montana as a state with losses and West Virginia and Nevada, among others, as states with lower profit margins. It is slightly challenging, however, to identify which states grossed the highest profit, as hues of the green color at a higher profit level look very similar, and that is one of the main disadvantages of using this type of map. An alternative to overcome this problem will be creating a sorted bar chart, which, if plotted correctly, will help the reader identify similar states without any guesswork.
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