Working with Charts (Report Builder 1.0)
A chart is a graphical representation of the data in a report. Displaying data as a chart is visually appealing and makes it easy for users to see comparisons, patterns, and trends in the data. For example, instead of having to analyze several columns of data in a table or matrix report, you can see at a glance whether sales are decreasing or increasing over the past three quarters, or how year-to-date sales compare for the past three years. In Report Builder, you can select from a variety of chart types and change a chart's style to include different colors, symbols, and three dimensional (3-D) effects.
The Chart control used in Reporting Services is licensed from Dundas Software. For more information about charting functionality available from Dundas Software, visit the company Web site at www.dundas.com.
Report Builder charts use three axes to group the data: Value, Category, and Series. Charts typically have two axes used to categorize and measure the data: a category (x) axis and a value (y) axis. The y-axis is usually the vertical axis and contains the data from the Value tab. The x-axis is usually the horizontal axis and contains the categories from the Category tab. The points on the resulting chart contain the data series from the Series axis. The Series axis is called the (z) axis. Pie and doughnut charts do not have axes. To display the axes areas, click the chart first. A chart report layout appears similar to the following image.
To add data to the chart layout, drag the fields that you want from the Explorer pane to the appropriate group. To better understand how these different groups behave, it might be helpful to compare a chart layout to a matrix layout. The fields in a Value group are the equivalent of static rows or columns in a matrix layout. The fields in a Category group are the equivalent to dynamic column groups in a matrix layout. The fields in a Series group are the equivalent to dynamic rows in a matrix layout.
The Value group is used to determine the size of the chart element for each category group. For example, a Values field determines the height of a column in a column chart or the size of a slice in a pie chart.
When you design a chart report, you need to add at least one field to the Value group. Value groups are static in charts. If you add only one field to the Value group and you do not add a field to the Series group, only a single chart element is displayed. If you add multiple fields to the Value group, a chart element is displayed for each value. If there are multiple fields in the Value group, the chart legend displays the name of each value.
Typically, data is grouped by category in a chart. If you are grouping your data based on category, you must use an aggregate field in the Value group. If you are grouping your data based on series, you must use an aggregate field in the Value group also. If you are not grouping data because you have only one field in the Category group, you do not need to use an aggregate field in the Value group.
The Category group is used to group your data. The name of each field is used to label the chart elements. For example, in a column chart, the name of each field in the Category group is placed on the x-axis of the chart, one for each set of columns.
You can nest categories. When you drag multiple fields on to the Category tab, each category is nested within another category. For example, in a column chart that displays products by model, the first category group would be model, and the second category group would be product. The column chart would display groupings of products by model on the x-axis. Category fields are dynamic.
The Series group is used to add an additional dimension to the data in your report. For example, in a column chart that displays sales by product, you can add a field to the Series group to display sales by year for each product. You are not required to add a field to the Series group; it is optional when designing a chart.
If you do use a Series group, the name of the group is placed in the legend of the chart. Series groups are dynamic.