Pie charts, circle graphs, nautical charts, line graphs: Charts and graphs sometimes seem the same, but other times they can seem very different. The confusion over charts and graphs may be frustrating at first, but it's easy to learn the differences and clear up that confusion.
TL;DR (Too Long; Didn't Read)
Charts present information in graphs, diagrams and/or tables. Graphs comprise a specific type of chart, showing the relationships between mathematical data.
Same, but Different
Charts present information in the form of graphs, diagrams or tables. Graphs show the mathematical relationship between sets of data. Graphs are one type of chart, but not the only type of chart; in other words, all graphs are charts, but not all charts are graphs. Charts are a large group of methods for presenting information. Graphs provide one of those methods by presenting data in a visual format.
The information in a chart often supports text, but sometimes the chart stands alone. Whether a diagram, a graph or a table, the information presented in charts should be clear to the reader. Diagrams can show sequential events like the rock cycle or the history of the U.S. government's nutritional guidelines. Other charts may show numerical data arranged in tables, like the MyPlate calorie guide, the CDC Drunk Driving State Data and Maps or the multiplication tables found in most classrooms. Maps comprise another category of charts, with information shown in relation to geography. Examples of charts using maps include drunk driving statistics or earthquake and volcano locations.
Graphs are Charts
Graphs form a subgroup of charts. Graphs specifically present mathematical relationships in data sets. In other words, graphs make pictures of numerical information.
Graphs can be simple, or they can be quite complicated, but they should always be selected to present their data as clearly as possible. Sometimes two graphs are better than one, if each graph shows a different aspect of the same data set. Not all graphs are created equal, however. The type of graph used depends on the type of data.
Types of Graphs
Bar graphs compare discrete sets of data. If one set of data doesn't influence the other set of data, a bar graph might be the best choice. For example, comparing drunk driving arrests in different states would use a bar graph, or comparing average heights of fifth-grade boys and girls.
Line graphs show changes in a group. Types of data graphed on line graphs include changes over time and changes with temperature. Plant growth over time, change in height with age, change in volume with temperature – these data sets should be graphed using line graphs.
Pie charts, also known as circle graphs, depict parts of a whole. The pie wedges add up to one complete pie. Statistics related to a closed population can be presented in pie charts. Demographics, for example, work well, if each member falls into one of the distinct groups. The numbers must graph as percentages that add up to 100 percent or as numbers that add up to equal the total population. For clarity, pie charts should not have too many pieces, however. Pie charts work best when not too cluttered.
Bar graphs, line graphs and pie charts may be the most commonly used graphs, but many other kinds of graphs exist. Many special graphs only appear occasionally, and many have limited applications in specific fields. But, simple or fancy, all graphs belong to the larger group called charts.
- University of North Carolina at Chapel Hill: Figures and Charts
- Centers for Disease Control: Using Graphs and Charts to Illustrate Quantitative Data
- Government of Canada: Statistics Canada: Graph Types - Using Graphs
- US Geological Survey: The Rock Cycle
- US Department of Agriculture: My Plate Plan - Choose My Plate
- Centers for Disease Control and Prevention: Drunk Driving State Data and Maps
- US Geological Survey: Geology Resources and PDF Images to Download