## Chapter 15 Displaying Data in Charts

You use the same sorts of data sources for a chart as you do for other report elements. Connecting with data sources and creating data sets are topics that are discussed earlier in this book.

How you return and arrange chart data is often different from the way in which you use data elsewhere in BIRT. One important difference is the data set that you create for a chart. Charts do not aggregate data. To use totals in a chart, you must create a data set that returns total information, which is why we showed you how to do that in the tutorial that appears earlier in this book.

Another difference is the way in which you can manipulate chart data to make it more effective or visually appealing. You provide expressions that organize the data into visual elements, such as bars or lines. After you preview the chart, you may feel that you need additional or different data to make the meaning of the chart more complete or clear. For example, you can group data values or use chart axis settings to modify the range, scale, or formatting of the data that the chart displays.