Creating Themes

Themes are styles based on the data associated with features in your map. Themes provide a visual representation of the data. For example, a typical theme for a point layer might display retail store locations with a different symbol for each type of store, or a polygon layer theme might display each land use classification with a different color or shading.

A theme consists of a collection of rules. Each rule specifies a style and feature label for the features that meet the specified condition. You can add a legend label to provide a description of a rule’s condition. As a layer is drawn, each feature is compared to the rules in the order that they are listed. The first rule for which the feature meets the condition is used to specify the style and feature label for that feature. A default or empty condition applies to all features and defines the style for features that do not meet any of the preceding rules. A well-constructed theme contains only one default rule and it is last in the list.

Create rules manually or use the Infrastructure Studio theming tool to automate theming based on a range of conditions. For more information, see Creating Themes Automatically.

To create a theme manually

1. Open the layer to edit by doing one of the following:
   • Create a new layer.
   • Double-click an existing layer.
   • Click the layer’s tab if the layer is already open.

   For information about creating a new layer, see Creating New Resources. For information about associating a data resource with a new layer, see Specifying the Data Resource for a Layer.

2. In the Style pane of the Layer Editor, under Scale Ranges, select the scale range to theme.

   For more information about scale ranges, see Understanding Scale Ranges.

3. In the geometry style area, click Theme>> if the style rule grid is not displayed.
4. In the style rule grid, click the Condition grid cell.
5. Use the Filter dialog box to specify the subset of features to theme. Click OK.

   For more information about using the Filter dialog box, see Filtering Data.

6. In the style rule grid, click the Style grid cell.

   The Style Point, Style Line, or Style Area dialog box is displayed depending on the type of data associated with the layer.

7. Create point, line, and area styles for the theme.

   For more information about defining styles, see Styling Points, Styling Lines, and Styling Areas.

8. To add labels to features in the theme, in the style rule grid, click the Feature Label grid cell.

   For more information about creating feature labels, see Adding Labels to Features.

9. To label the theme in the legend, enter the text in the Legend Label grid cell.
10. Optionally, do one or more of the following:
    • To add a new rule to an existing theme, click Add A Rule.

      Define the rule as described in the preceding steps.

    • To copy and modify a selected rule, click Duplicate.

      Modify the new rule as described in the preceding steps.

    • To delete the selected rule, click Delete.
    • To adjust the position of the selected rule in the list, click Move Up and Move Down as needed.

      After a rule applies to a feature, none of the rules that come after it in the list are applied to the feature.

11. Click File menu Save.