Class breaks rendering

Class breaks rendering can be used to symbolize layers that allow configuration of symbology. This includes ArcGIS Server feature layers, tables from Spatial Data Service endpoints, geoRSS layers, and graphics layers. For more information on the different layer types and their capabilities, see Layer types.

About class breaks

Class breaks are simply categories, each with a minimum and maximum value. When applied to a set of data, class breaks divide the data into categories based on the value of a certain field or attribute. Since the definition of a class depends on having a minimum and maximum value, class breaks are only applicable to numeric attributes. A class breaks renderer maps each class to a particular symbol. Graphics with similar values for the attribute get the same symbol.

As an example, suppose you have a buildings layer with an attribute that specifies the year each building was built. You want to symbolize buildings constructed since the year 2000 in green, buildings constructed between 1980 and 2000 in yellow, and buildings built before 1980 with red. Suppose that the earliest a building represented in the layer was constructed is 1960. In this case, you would define classes of 1960–1979, 1980–1999, and 2000–2012.

Configuring a class breaks renderer

The ArcGIS Viewer for Silverlight makes it simple to apply class breaks rendering to a layer. To do so, follow these steps:

  1. Choose the layer you want to configure class breaks for from the Configure Layers panel.
  2. Right-click the layer and click Configure. Alternatively, click the Configure button at the bottom of the Configure Layers Panel:
    Configure layer
  3. On the Configuring panel that appears, click Symbology to view the configuration options:
    Symbology menu
  4. Expand the Renderer drop-down menu and choose Class Breaks. The Application Builder automatically calculates five class breaks for the first numeric field in the layer:
  5. Now configure the renderer:
    • Changing the attribute—To change the field on which the symbols are based, expand the Attribute drop-down menu and click the desired field:
      Magnitude attribute selected
    • Changing the color scheme—You can apply a predefined color scheme to the renderer by clicking the Color Scheme button on the ribbon and choosing the desired color scheme from the list that appears:
      Class Breaks color scheme
    • Selecting a value's symbol—To specify the symbol for one value, click the symbol to the left or the Down arrow to the right of the value. Then choose the desired symbol from the symbol picker:
      Symbol picker dialog box
    • Modifying a value's symbol—To modify the symbol used by a value, first select the value from the right side of the dialog box. Then use the controls in the Current Symbol section of the dialog box to adjust the symbol's size, color, and transparency.
      The size and color controls that are enabled vary depending on the geometry type of the selected layer. For further information about specifying a symbol's size and color, see Single symbol rendering. The number of transparency sliders enabled also varies depending on the geometry type of the selected layer. For line and point layers, only one slider is enabled. In this case, the enabled slider determines the transparency of the entire symbol. For polygon layers, both sliders are enabled. The top slider determines the transparency of the symbol's fill, while the bottom slider determines the transparency of the symbol's border.
    • Changing a class's value range—The minimum and maximum values of a class can be changed by clicking a value and typing a new value:

      Class value range selector