A line chart presents values as a series of sloped lines, or as a smooth curve. For example, the standard summary-type report, pyArrivalsPastAEightWeeksSV includes a line chart depicting how many new work items were started in each of the last eight weeks.
Line charts used with Report Definitions can be of several different subtypes.
You can use a line chart to display the data in a Report Definition report by selecting the chart type in the toolbar at the top of the Chart Editor.