A picture graph's pictures or small symbols that represent quantities compare the amounts of different items tracked, or how the amount of an item changes over a period of time. For example, a picture graph may show how many people prefer each of a few choices of food, or it may show how many people purchased a specific item in each month of one year. Picture graphs generally are used to present data relating to the amount of a particular item. They are used frequently in content intended for young children and to convey non-complex data to a large audience.
A picture graph can be presented vertically or horizontally. The items the graph compares are listed along the side of a horizontal graph and along the bottom of a vertical graph. The symbols representing amounts are inside the graph, next to each item. Each picture may represent more than one item. For example, a stick figure may represent one person, 10 people or 1,000 people. Picture graphs usually include a key that states the amount that a symbol represents. One-half of a symbol represents one-half of the amount specified for a complete symbol.
Data displayed in a picture graph can be displayed in a bar graph. Sometimes picture graphs are preferred because they are easier to understand than bar graphs. Even someone who has never seen a picture graph before usually can quickly figure out its meaning. A disadvantage of picture graphs, however, is that they are very simplistic. They cannot display data with more than two components easily, unlike a bar graph or line graph. Therefore, they are not used frequently to represent complex financial or scientific data.
The subject of picture graphs is often taught to first- and second-grade students as their introduction to the use of graphs, and they are covered in elementary schools' early math curriculum. Standardized tests often require students to understand and create all types of graphs, including picture graphs. Picture graphs are commonly featured in science and social science textbooks at all levels to illustrate data. Understanding how they work helps in many academic areas.