Why Area charts in Tableau? - Purpose & Use Cases

The Big Idea

What if you could see your data's story unfold smoothly over time with just one simple chart?

The Scenario

Imagine you have monthly sales data in a spreadsheet and want to show how sales grow over time. You try to draw this by hand or use simple bar charts, but it's hard to see the overall trend and how different parts add up.

The Problem

Manually creating visuals or using basic charts can be slow and confusing. You might miss patterns or relationships because bars or lines alone don't show the full picture of accumulation or proportion over time.

The Solution

Area charts fill the space under the line, making it easy to see total values and how parts contribute to the whole over time. Tableau lets you create these charts quickly, showing trends and volumes clearly in one view.

Before vs After

✗ Before

Create separate bar charts for each month and try to compare visually.

✓ After

Use Tableau's area chart to plot sales over months with filled areas showing growth.

What It Enables

Area charts let you instantly grasp how values accumulate and change over time, revealing trends and proportions at a glance.

Real Life Example

A marketing manager tracks website visits monthly. Using an area chart, they see how traffic grows and which campaigns add the most visitors, helping plan future strategies.

Key Takeaways

Manual charts can hide trends and relationships.

Area charts fill space to show totals and parts clearly.

Tableau makes creating area charts fast and insightful.

Practice

1. What is the main purpose of an area chart in Tableau?

easy

A. To show trends and the total amount by filling the area under a line

B. To display individual data points without connecting lines

C. To compare categories using bars of different lengths

D. To show relationships between two numerical variables using dots

Solution

1. Step 1: Understand area chart basics

   An area chart fills the space under a line to emphasize the magnitude of values over time or categories.

2. Step 2: Compare with other chart types

   Unlike scatter plots or bar charts, area charts focus on trends and totals by shading the area below the line.

3. Final Answer:

   To show trends and the total amount by filling the area under a line -> Option A

4. Quick Check:

   Area chart = filled trend line [OK]

Hint: Area charts fill space under lines to show totals [OK]

Common Mistakes:

• Confusing area charts with scatter plots
• Thinking area charts only show individual points
• Using area charts to compare unrelated categories

2. Which of the following is the correct way to create an area chart in Tableau?

easy

A. Drag a measure to Filters, a dimension to Pages, then select 'Line' mark type

B. Drag a dimension to Rows, a measure to Columns, then select 'Circle' mark type

C. Drag two measures to Rows and Columns, then select 'Bar' mark type

D. Drag a measure to Rows, a dimension to Columns, then select 'Area' mark type

Solution

1. Step 1: Identify correct field placement

   For area charts, a measure (numeric data) goes on Rows and a dimension (categories or time) on Columns.

2. Step 2: Choose the correct mark type

   After placing fields, select the 'Area' mark type to fill the area under the line.

3. Final Answer:

   Drag a measure to Rows, a dimension to Columns, then select 'Area' mark type -> Option D

4. Quick Check:

   Measure + Dimension + Area mark = Area chart [OK]

Hint: Measure on Rows + Dimension on Columns + Area mark [OK]

Common Mistakes:

• Using Circle or Bar mark types instead of Area
• Placing dimensions on Rows instead of Columns
• Not selecting the Area mark type after placing fields

3. Given a dataset with sales over months and product categories, what will happen if you create an area chart with Month on Columns, SUM(Sales) on Rows, and Category on Color?

medium

A. The chart will show stacked colored areas for each category over months

B. The chart will show separate lines without filled areas

C. The chart will show a single color area for total sales only

D. The chart will produce an error because color cannot be used here

Solution

1. Step 1: Understand field roles in area chart

   Month on Columns creates the timeline, SUM(Sales) on Rows shows total sales, and Category on Color splits the area by product categories.

2. Step 2: Visualize the result

   Each category's sales area stacks on top of others, showing contribution per month with different colors.

3. Final Answer:

   The chart will show stacked colored areas for each category over months -> Option A

4. Quick Check:

   Color by category = stacked colored areas [OK]

Hint: Color splits area into stacked parts by group [OK]

Common Mistakes:

• Expecting separate lines instead of stacked areas
• Thinking color only changes line color, not area
• Assuming color cannot be used with area charts

4. You created an area chart but the areas overlap and colors are not stacked. What is the most likely cause?

medium

A. The color field is missing or not assigned

B. The dimension is on Rows instead of Columns

C. The mark type is set to 'Line' instead of 'Area'

D. The measure is aggregated incorrectly

Solution

1. Step 1: Check the mark type

   If the mark type is 'Line', the chart shows lines without filled areas, causing overlap and no stacking.

2. Step 2: Confirm correct mark type for area chart

   Changing the mark type to 'Area' fills the space under the lines and stacks colors properly.

3. Final Answer:

   The mark type is set to 'Line' instead of 'Area' -> Option C

4. Quick Check:

   Line mark = no filled areas [OK]

Hint: Use 'Area' mark type to avoid overlapping lines [OK]

Common Mistakes:

• Ignoring mark type and blaming data placement
• Not assigning color field for stacking
• Misunderstanding aggregation effects on area charts

5. You want to compare monthly sales trends for two regions using an area chart in Tableau. Which approach best highlights differences clearly?

hard

A. Place Region on Columns, Month on Rows, and SUM(Sales) on Size with 'Circle' mark type

B. Place Month on Columns, SUM(Sales) on Rows, and Region on Color with 'Area' mark type

C. Place Month on Rows, Region on Columns, and SUM(Sales) on Rows with 'Bar' mark type

D. Place SUM(Sales) on Columns, Month on Rows, and Region on Detail with 'Line' mark type

Solution

1. Step 1: Set timeline and measure correctly

   Month on Columns creates the timeline axis, SUM(Sales) on Rows shows sales values.

2. Step 2: Use Region on Color with Area mark

   Assigning Region to Color splits the area chart into colored stacked or overlapping areas per region, making differences visible.

3. Final Answer:

   Place Month on Columns, SUM(Sales) on Rows, and Region on Color with 'Area' mark type -> Option B

4. Quick Check:

   Color by region + Area mark = clear comparison [OK]

Hint: Use color for groups and area mark for trends [OK]

Common Mistakes:

• Using Circle or Bar marks instead of Area
• Placing Region on Columns instead of Color
• Not using Month on Columns for timeline