Bar chart

A bar chart is a type of chart which shows the values of different categories of data as rectangular bars with different lengths. A histogram is a bar chart that shows how data is spread over its categories.

A bar chart.

It is another one dimensional diagram also known as pillar diagram or column graph. These bars do not have any specific width but the height of the bar is proportionally to the value of an element. When the variations are small this method is very efficient.