Visionary User's Guide Chapter 8: Adding Navigation Features to a Scene

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Adding Levels of Detail A level of detail (shown in the interface as LOD) is a view of data associated with a zoom level. Levels of detail enable you to present more (or less) information as you zoom in on a scene or data point. As you zoom in, there are fewer data points displayed, and more screen area is available for showing details. You can create levels of detail for scenes or for data elements. Every data element and scene you create has a default level of detail that is viewed when the scene is at 100% zoom. Levels of Detail in a Data Element Different levels of detail in a single data element use the same layout and data source at each level of detail. For example, a scene might display a scatter chart. At 100% zoom level, the points on the chart could be represented by markers. If you created a second level of detail at 200%, you could display the actual numerical values when your user zooms in. Figure 8-2 illustrates two levels of detail in a data element. Figure 8-2 Levels of Detail in a Data Element In this example, the data element at 100% zoom level is a marker selected from the Data Symbols panel. At 200% zoom level, the data element is a text object mapped to a numerical value returned from the database. For more information about levels of detail in data elements, see Chapter 5, "Displaying Data in a Scene." Levels of Detail in a Scene Different levels of detail in a single scene use different layouts and data sources at each level. Levels of detail in a scene enable you to create different combinations of data. For example, a scene with a candlestick chart representing stock performance over time could have a second level of detail with a different scene presenting the text of relevant news articles. Figure 8-3 illustrates levels of detail in a scene. Figure 8-3 Levels of Detail in a Scene In this example, the scene at 100% zoom level shows a candlestick chart layout that presents the stock data, using a data source from a table containing financial and calendar data. Zooming to 200% reveals a different scene that displays a simple form that presents a news article. The scene displaying the news article uses a data source from a different table containing dates and article texts. To insert a level of detail into a scene In the Scene Editor, click the LOD list box and select (New) or choose Insert Level of Detail (LOD). Figure 8-4 illustrates the LOD list box. Figure 8-4 LOD List Box After you have inserted a new level of detail, you can insert layouts and primitive objects to display the additional data you want to show when your user zooms in on the scene. Levels of detail have a level of detail transition point, which is the minimum zoom level at which the next level of detail becomes visible. When you insert a level of detail, the default level of detail transition point for the new level of detail is 200%, or twice the previous level of detail. If the level of detail transition point for a scene is 200% and the user zooms to 150%, the scene is magnified, but the second level of detail does not appear. If the data in a layout is clustered together, you might want to set the level of detail transition point to a zoom level greater than the default. This would let users see the information at the first level of detail more clearly before the display switches to the second level. To change a level of detail transition point 1. In the Scenes panel, right-click the level of detail and select Edit LOD Transitions from the popup menu. 2. In the Level of Detail Transition Editor dialog box, enter desired zoom levels for each LOD transition point. 3. Click OK. Tip: When you add a new LOD to a scene or data element, the transition level for the new LOD is automatically set to twice the zoom level of the previous LOD.