Dual-axis maps in Tableau - Real Business Scenario

Scenario Mode

👤 Your Role: You are a sales analyst at a retail company.

📋 Request: Your manager wants a map that shows both store locations and sales volume by region on the same visual to better understand geographic sales performance.

📊 Data: You have data with store names, their latitude and longitude coordinates, sales volume, and region names.

🎯 Deliverable: Create a dual-axis map in Tableau that overlays store locations as points and sales volume by region as filled map areas.

Sample Data

Store Name	Latitude	Longitude	Sales Volume	Region
Store A	40.7128	-74.0060	120000	East
Store B	34.0522	-118.2437	95000	West
Store C	41.8781	-87.6298	110000	Central
Store D	29.7604	-95.3698	85000	South
Store E	39.9526	-75.1652	105000	East
Store F	33.4484	-112.0740	90000	West
Store G	39.7392	-104.9903	80000	Central
Store H	32.7767	-96.7970	75000	South

1

Step 1: Connect your data source in Tableau and load the sample data.

Use the provided data with Store Name, Latitude, Longitude, Sales Volume, and Region columns.

Expected Result

Data is loaded and visible in Tableau's Data pane.

2

Step 2: Create the first map layer showing store locations as points.

Drag Longitude to Columns and Latitude to Rows. Change the mark type to 'Circle'. Drag Store Name to Detail and Sales Volume to Size.

Expected Result

Map shows points for each store sized by sales volume.

3

Step 3: Create the second map layer showing sales volume by region as filled areas.

Duplicate the Longitude and Latitude fields on Columns and Rows to create a second map. Change the mark type to 'Map'. Drag Region to Color and SUM(Sales Volume) to Color.

Expected Result

Map shows regions filled with color intensity representing total sales volume.

4

Step 4: Combine the two maps using dual-axis to overlay points on filled regions.

Right-click the second Longitude axis and select 'Dual Axis'. Synchronize axes by right-clicking one axis and selecting 'Synchronize Axis'.

Expected Result

Single map view with store points over colored regions.

5

Step 5: Format the map for clarity and accessibility.

Adjust point sizes for visibility, choose contrasting colors for regions and points, add map title and legend, and ensure colorblind-friendly palette.

Expected Result

Clear, accessible dual-axis map showing store locations and regional sales volume.

Final Result

-------------------------------------------------
|                 Dual-Axis Map                  |
|                                               |
|  [Colored regions by sales volume]             |
|   +   +   +   +   +   +   +   +   +   +       |
|  +  o Store points sized by sales volume  +    |
|   +   +   +   +   +   +   +   +   +   +       |
|                                               |
| Legend:                                       |
|  ■ Region color intensity = Sales Volume      |
|  ● Point size = Store Sales Volume             |
-------------------------------------------------

✓East region has the highest total sales volume.

✓Store A has the largest sales volume among individual stores.

✓Stores are well distributed geographically across regions.

✓Dual-axis map helps visualize both regional trends and individual store performance simultaneously.

Bonus Challenge

Add a filter to the dashboard to allow users to select specific regions and see the map update dynamically.

Show Hint

Use Tableau's filter action on the Region field and apply it to both map layers to keep the dual-axis map synchronized.

Practice

1. What is the main purpose of using dual-axis maps in Tableau?

easy

A. To layer two map types for better comparison or detail

B. To create a 3D map visualization

C. To filter data based on geographic regions

D. To export maps as images

Solution

1. Step 1: Understand dual-axis maps concept

   Dual-axis maps combine two map layers in one view to show more information.

2. Step 2: Identify the main use

   This layering helps compare or add details like points over filled areas.

3. Final Answer:

   To layer two map types for better comparison or detail -> Option A

4. Quick Check:

   Dual-axis maps = layering two map layers [OK]

Hint: Dual-axis maps layer two map types in one view [OK]

Common Mistakes:

• Thinking dual-axis maps create 3D maps
• Confusing dual-axis maps with filtering
• Assuming dual-axis maps export images

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

easy

A. Create two separate worksheets and combine them in a dashboard

B. Drag one geographic field to Columns and filter by region

C. Use the 'Show Me' panel and select 'Pie Chart'

D. Drag two geographic fields to Rows and then right-click one and select 'Dual Axis'

Solution

1. Step 1: Identify how to create dual-axis maps

   In Tableau, you drag two geographic fields to Rows or Columns, then right-click one and choose 'Dual Axis'.

2. Step 2: Eliminate incorrect options

   Filtering or using 'Show Me' pie chart does not create dual-axis maps; separate worksheets are not dual-axis maps.

3. Final Answer:

   Drag two geographic fields to Rows and then right-click one and select 'Dual Axis' -> Option D

4. Quick Check:

   Dual axis = right-click axis > Dual Axis [OK]

Hint: Right-click axis and choose 'Dual Axis' to combine maps [OK]

Common Mistakes:

• Trying to create dual-axis maps via filtering
• Using 'Show Me' for map layering
• Combining worksheets instead of dual-axis

3. Given two map layers: one showing filled states and another showing city points, what happens if you do NOT synchronize the axes in a dual-axis map?

medium

A. Tableau will automatically merge the layers perfectly

B. The two layers may not align correctly on the map

C. The map will show only one layer

D. The map will display a blank view

Solution

1. Step 1: Understand axis synchronization

   Synchronizing axes ensures both map layers use the same scale and position.

2. Step 2: Consequence of not synchronizing

   Without synchronization, layers may shift and not align properly, causing visual mismatch.

3. Final Answer:

   The two layers may not align correctly on the map -> Option B

4. Quick Check:

   Unsynchronized axes = misaligned layers [OK]

Hint: Always synchronize axes to align map layers correctly [OK]

Common Mistakes:

• Assuming Tableau auto-aligns layers without sync
• Thinking map shows only one layer if unsynced
• Believing unsynced axes cause blank maps

4. You created a dual-axis map but the points layer is not visible on top of the filled map layer. What is the most likely cause?

medium

A. The points layer is hidden behind the filled map layer

B. The marks card for the points layer is set to 'Circle' with zero size

C. The layers are not synchronized

D. The data source is disconnected

Solution

1. Step 1: Check layer order in dual-axis maps

   In dual-axis maps, one layer can hide another if it is on top and opaque.

2. Step 2: Identify why points are invisible

   If points are hidden behind the filled map layer, they won't be visible even if present.

3. Final Answer:

   The points layer is hidden behind the filled map layer -> Option A

4. Quick Check:

   Layer order affects visibility in dual-axis maps [OK]

Hint: Check layer order if points are invisible [OK]

Common Mistakes:

• Assuming unsynchronized axes hide points
• Thinking zero size circle is default
• Blaming data source without checking layers

5. You want to create a dual-axis map showing sales by state as filled areas and customer locations as points. Which steps ensure the map layers align and display correctly?

hard

A. Drag State to Rows, Customer Latitude and Longitude to Rows and Columns, create dual axis, then do NOT synchronize axes

B. Drag State to Detail on one Marks card, Customer Latitude and Longitude to Rows and Columns, create dual axis, then synchronize axes

C. Drag State to Color, Customer Latitude and Longitude to Rows and Columns, create dual axis, then synchronize axes

D. Drag Customer Latitude and Longitude to Rows and Columns, create dual axis, then filter by State

Solution

1. Step 1: Assign State to Color for filled areas

   Using State on Color fills the map areas by state, showing sales distribution.

2. Step 2: Use Customer Latitude and Longitude on Rows and Columns

   These geographic fields plot customer points on the map.

3. Step 3: Create dual axis and synchronize axes

   Dual axis layers the filled states and points; synchronization aligns them correctly.

4. Final Answer:

   Drag State to Color, Customer Latitude and Longitude to Rows and Columns, create dual axis, then synchronize axes -> Option C

5. Quick Check:

   State on Color + Lat/Long + dual axis + sync = correct map [OK]

Hint: Use State on Color and synchronize axes for correct layering [OK]

Common Mistakes:

• Putting State on Detail instead of Color
• Not synchronizing axes after dual axis
• Dragging State to Rows instead of Color