Basic Pictographs: Reading a Picture Graph

A pictograph, sometimes called a picture graph, is a way to show information using small pictures or symbols instead of numbers or bars. Each row (or column) stands for one category, and the number of symbols in that row tells you how much that category has. Pictographs are one of the easiest ways to see and compare data at a glance, which is why they usually come right after a lesson on collecting data and just before you learn to build a bar graph.

Every basic pictograph has three main parts:

• A title that tells you what the graph is about.
• A list of categories, each with its own row of symbols.
• A key that explains how many items one symbol represents.

The key is the most important part of a pictograph, and it is also the part students forget to check first. If a key says one symbol equals 2 pets, then a row with three symbols does not mean 3 pets, it means \(3 \times 2 = 6\) pets. Always read the key before you count any symbols, because the same picture graph can mean very different things depending on what value each symbol stands for.

Sometimes a row will end with only half a symbol. A half symbol simply means half of the key value. If each symbol equals 2, then a half symbol equals 1.

Look at the pictograph below, which shows how many pets of each type were counted in a class survey. Each circle in the key equals 2 pets.

To read this basic pictograph, work one row at a time:

• Dogs has 3 full circles, so \(3 \times 2 = 6\) dogs.
• Cats has 2 full circles, so \(2 \times 2 = 4\) cats.
• Fish has 1 full circle and 1 half circle, so \(2 + 1 = 3\) fish.
• Birds has 2 full circles and 1 half circle, so \(4 + 1 = 5\) birds.

Once every row is turned into a number, you can quickly compare the categories. In this survey, dogs are the most popular pet and cats are the least popular, since 6 is the greatest total and 4 is the smallest.

Pictographs are especially useful for answering questions like "how many more" or "how many fewer." Using the pets example, dogs \((6)\) minus cats \((4)\) gives \(6 - 4 = 2\), so 2 more people chose dogs than cats. Practicing these comparisons alongside words like "more than," "fewer than," and "the same as" is covered in more depth in the comparative language lesson.

To build your own pictograph from a set of data, follow these steps:

• Choose a simple symbol that is easy to draw the same way every time.
• Pick a key value that divides your data into a manageable number of symbols, such as 1, 2, 5, or 10 per symbol.
• Draw one row per category and place the correct number of symbols, using a half symbol for leftover amounts.
• Write the key clearly so anyone reading the graph knows what each symbol is worth.

Once you are comfortable with pictographs, the next natural step is representing the same kind of data with rectangles instead of symbols, which is exactly what you do in bar graphs.

Working through several pictograph examples is the best way to get comfortable with reading keys and counting symbols quickly. A good pictograph worksheet will usually mix full and half symbols, different key values, and at least one "how many more or fewer" question, so you practice both reading the picture graph and using the numbers you find from it.

Related lessons

• Math 2