About Interval Themes
Interval themes provide a method to render different features with different symbols based on a range of attribute values. For example, assume there is a point based map of cities. With an interval theme it is possible display cities with population less that 100,000 with one symbol, cities with a population between 100,000 and 250,000 with a different symbol, and so on.
Steps For Adding An Interval Theme
- Right-click on the layer in the legend. A new menu will popup.
- Click on Layer Properties. The Layer Properties dialog will be displayed.
- Click the Themes tab.
- Click the Interval button under the New Themes section.
- The Interval Theme dialog will display. Type in a theme name. For example, 'City Population'.
- Select the Source Column that will supply the values that each symbol will be based on. Interval themes are limited to numeric fields.
- The default symbology will be built based on a color ramp. Choose the starting and ending colors for this ramp.
- Select the number of intervals you wish to create. AccuGlobe will automatically create equal intervals, but it can be customized later.
- Click the Build Ramp button.
- The list will populate with the upper bound of each interval and the corresponding symbol color.
- Click on the upper bound of any particular interval to change it.
- Click each symbol entry in the list and specify the symbol properties for each one using the color, size and style settings.
- To specify a custom pen style, use the browse button to select a custom icon file that will be used to render the map feature.
- To specify a custom fill style, use the browse button to select a custom bitmap file that will be used to fill the map feature.
- If map units have been set for the project it is possible to make the value theme scale dependent.
- Click the OK button to add the theme.
- To make further changes to your interval theme, select it from the list and click the Edit button.
- To remove the interval theme select it from the list and click Remove.
- Click the Close button to exit the Layer Properties dialog. The map will redraw and apply your changes.
It is possible to save the current settings for this theme and then load these settings into another label theme for another layer. This functionality is assessible via a template selector screen where templates will be displayed by filename and their description.
A screenshot of an example default interval theme is shown below: