Why Filled maps (choropleth) in Tableau? - Purpose & Use Cases

The Big Idea

What if you could see your data's story on a map in seconds, not hours?

The Scenario

Imagine you have a list of sales numbers by state in a spreadsheet. You want to see which states sell the most. You try coloring each state manually by looking up numbers and shading them in a map image. It takes hours and looks messy.

The Problem

Manually coloring states is slow and mistakes happen easily. You might color the wrong state or use inconsistent shades. Updating the data means starting over. It's hard to see patterns quickly or share results clearly.

The Solution

Filled maps (choropleth) in Tableau automatically color regions based on your data. You just drag your sales numbers and location fields, and Tableau paints the map for you. It updates instantly when data changes, making insights clear and fast.

Before vs After

✗ Before

Color each state on a static map image by hand.

✓ After

Drag 'State' to the map, drag 'Sales' to Color in Tableau.

What It Enables

Filled maps let you instantly spot trends and differences across regions, making data stories clear and powerful.

Real Life Example

A retail manager uses a filled map to see which states have the highest sales, helping decide where to open new stores.

Key Takeaways

Manual coloring is slow and error-prone.

Filled maps automate coloring by data values.

They reveal geographic patterns clearly and quickly.

Practice

1. What is the main purpose of a filled map (choropleth) in Tableau?

easy

A. To color geographic areas based on data values

B. To display detailed street-level maps

C. To show individual data points as dots

D. To create 3D maps with elevation

Solution

1. Step 1: Understand filled map concept

   A filled map colors entire geographic areas (like states or countries) based on data values.

2. Step 2: Compare with other map types

   Unlike dot maps or 3D maps, filled maps focus on coloring regions, not points or elevation.

3. Final Answer:

   To color geographic areas based on data values -> Option A

4. Quick Check:

   Filled maps = color areas by data [OK]

Hint: Remember: filled maps color regions, not points or lines [OK]

Common Mistakes:

• Confusing filled maps with point maps
• Thinking filled maps show street details
• Assuming filled maps create 3D effects

2. Which of the following is the correct way to create a filled map in Tableau?

easy

A. Drag a geographic field to Filters and a measure to Size

B. Drag a measure to Rows and a geographic field to Tooltip

C. Drag a geographic field to Rows and a measure to Color on the Marks card

D. Drag a measure to Columns and a geographic field to Detail

Solution

1. Step 1: Identify how to build filled maps

   In Tableau, dragging a geographic field (like State) to Rows or Columns creates the map base.

2. Step 2: Add color by measure

   Placing a measure on Color in the Marks card colors the geographic areas based on data values.

3. Final Answer:

   Drag a geographic field to Rows and a measure to Color on the Marks card -> Option C

4. Quick Check:

   Geo field + Color measure = filled map [OK]

Hint: Put geography on Rows/Columns and measure on Color [OK]

Common Mistakes:

• Putting geographic fields in Tooltip instead of Rows/Columns
• Using Size instead of Color for data values
• Not dragging any measure to Color

3. Given a filled map showing sales by state, what will happen if you drag the Sales measure to the Color shelf and set the aggregation to SUM?

medium

A. Each state will be colored based on total sales in that state

B. The map will show individual sales transactions as dots

C. The map will display sales as labels on each state

D. The map will become blank because SUM is invalid here

Solution

1. Step 1: Understand SUM aggregation on measure

   SUM aggregates all sales values per state, giving total sales per state.

2. Step 2: Effect on filled map coloring

   Coloring by SUM(Sales) colors each state area based on its total sales amount.

3. Final Answer:

   Each state will be colored based on total sales in that state -> Option A

4. Quick Check:

   SUM(Sales) colors states by total sales [OK]

Hint: SUM on measure colors areas by total values [OK]

Common Mistakes:

• Thinking dots appear instead of colored areas
• Expecting labels instead of colors
• Assuming SUM aggregation causes errors

4. You created a filled map but the colors do not change when you drag your measure to Color. What is the most likely reason?

medium

A. The measure is not numeric

B. The map type is set to Symbol Map instead of Filled Map

C. You forgot to add the geographic field to Detail or Rows/Columns

D. The geographic field is not recognized correctly

Solution

1. Step 1: Check map type setting

   If the map type is Symbol Map, colors apply to points, not areas, so filled colors won't appear.

2. Step 2: Confirm filled map selection

   Switching to Filled Map enables coloring of geographic areas by measure values.

3. Final Answer:

   The map type is set to Symbol Map instead of Filled Map -> Option B

4. Quick Check:

   Symbol Map ≠ filled colors; choose Filled Map [OK]

Hint: Check map type: must be Filled Map for area colors [OK]

Common Mistakes:

• Assuming measure type causes no color change
• Not verifying map type in Marks card
• Ignoring geographic field placement

5. You want to create a filled map showing population density by US state, but your data only has total population and land area separately. How should you prepare your data in Tableau to color states by population density?

hard

A. Use total population as Color and filter states by land area

B. Drag total population to Color and land area to Size

C. Create a parameter for land area and use it to filter states

D. Create a calculated field dividing total population by land area, then drag it to Color

Solution

1. Step 1: Calculate population density

   Create a calculated field: Population Density = Total Population / Land Area.

2. Step 2: Use calculated field for coloring

   Drag this new field to Color on the Marks card to color states by density.

3. Final Answer:

   Create a calculated field dividing total population by land area, then drag it to Color -> Option D

4. Quick Check:

   Calculated field = density, use on Color [OK]

Hint: Calculate density first, then color map by it [OK]

Common Mistakes:

• Using raw population without area for color
• Using Size for land area instead of calculation
• Filtering states instead of calculating density