Area chart is a area graph which graphically displays quantitative data, also a line chart in which the areas below the lines are filled with colors.

Magnitude of the given observations are represented by the area diagram.The length as well as the width of the bars needs to be considered, and are said to be two dimensional diagrams. Commonly used two dimensional diagrams are rectangle, squares, circles and pie diagrams. 

Line charts and area charts are very closely related. Both display the continuity across a dataset. Useful for seeing trends rather than the individual values. Line charts are good for comparing different series and also comparing them against each other. Area chart is not good for comparing between many areas as they have problems with occlusion.
Line diagram is the simplest of all diagrams. Consist in drawing vertical lines, each vertical line being equal to the frequency. Useful for facilitating comparisons though they are not attractive or appealing to the eye. The variate values are presented on a suitable scale along y axis. Time series can also be presented on a line diagram. Line diagrams are also known as bar diagrams. They are said to be one dimensional as the magnitudes of the observations are represented by one of the dimensions length. Area chart gives a better look and presentation of the data helps user in having a grasp of the topic.
Some of the examples based on area chart are given below:

Example 1: Prepare a area diagram from the following particulars relating to the production of a commodity in a factory.
Units produced   
 $\$$ 1000
Cost of raw materials  $\$$ 5000
 Direct expenses  $\$$ 2000
 Indirect expenses      $\$$ 1000
 Profit $\$$ 1000

Solution:
For the given problem we need to find the cost of material, expenses and profits per unit as given below:

cost of raw material per unit : $\$$ $\frac{5000}{1000}$ = $\$$ 5

Direct expenses per unit : $\$$ $\frac{2000}{1000}$ = $\$$ 2

Indirect expenses per unit : $\$$ $\frac{1000}{1000}$ = $\$$ 1

Profit per unit : $\$$ $\frac{1000}{1000}$ = $\$$ 1

Diagram showing cost and profit for a commodity in a factory.
Area Chart

Example 2: The following data relates to the monthly expenditure in $\$$ of two families A and B.

   Expenditure (in $\$$)
 Item of Expenditure Family A  Family B
Food  160  120
 Clothing  80 32
 Rent 60  48
 Lights and fuel  20 16
 Miscellaneous 80 24
 Total 400 240

Represent the above data using a suitable diagram.

Solution: From the given data it is clear that the total expenses of the two families are different, an appropriate percentage diagram for the above data will be rectangular diagram on percentage basis. The percentage bar diagram will not be able to reflect the inherent differences in the total expenditures of the two families.

Widths of the rectangles will be taken in the ratio of the total expenses of the two families
400 : 240
$\rightarrow$5 : 3

Calculating percentages is shown below in the table.
  
Family A Family B
 Item of Expenditure  $\$$.  %  Cumulative %  $\$$. %  Cumulative %
 Food  160  40  40  120  50  50
 Clothing  80  20  60  32  13.33  63.33
 Rent  60  15  75  48  20  83.33
 Light and Fuel  20  5  80  16  6.67  90
 Miscellaneous  80  20  100  24  10  100
  Total  400  100    240  100  

Given below is the image.
Area Chart Example
Example 3: Draw a suitable diagram to represent the following information.

       Total cost in $\$$
  Selling price per unit (in $\$$.)  Quantity sold  wages  Materials  Misc.  Total
 Factory X  400  20 160  120  80  360
 Factory Y  600  30  200  200  300  700

Show also the profit or loss as the case may be.

Solution: Calculate the cost per unit as given in the below table.

     Cost per unit (in $\$$)  
Selling price per unit (in Rs.)  Quantity sold  wages  Materials  Misc.  Total Profit per unit (in $\$$)
 400  20 160  120  80  360  400 - 360 = 40
 600  30  200  200  300  700 600 - 700 = -100

Negative profit is regarded as loss.
An appropriate diagram for representing this data would be the 'Rectangles' whose widths are in the ratio of the quantities sold. 20 : 30
$\rightarrow$ 2 : 3
Selling is represented by the corresponding heights of the rectangles with various factors of cost and profit or loss represented by the various divisions of the rectangles as shown below.

Sub divided rectangle showing cost, sales and profit or loss per unit:

Area Chart Problem