Line graphs are those graphs which are used to show the progression of data in the form of a graph. Line graphs are most commonly used by scientists to demonstrate a scientific phenomenon. They are also used by businessmen to represent information on clients and business processes. Line graphs must be carefully constructed so that the information they are trying to impart comes across clearly and in a well defined manner.

Line graphs can depict single lines showing the progression of one set of data, or they can show the progression of more than one set of data with the help of many lines plotted on the same graph. Thus, such graphs are comparative in nature.

Line graphs are created by joining the various data points on the graph. Thus, they have a wide applicability and are one of the most commonly used graphs. Line graphs are easy to access and understand and they are relatively simple to create as well.

A key is a must in case of line graphs which deal with more than one set of data. This will help clarify the graph. The obrazom, the derivative, the covering graph and so on are also kinds of line graphs which are commonly used. However, these are technically more challenging than the simple line graph.