2 • Geographic Data Management

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After creating the catalog, you load raster datasets into it.

When you create a raster catalog, a table is created that lists each raster. You can display the table by selecting the catalog in the Catalog tree, selecting the Preview tab, and clicking the Table option at the bottom of the window. You can add fields to the table (such as source, creation date, and so on) to track the rasters. Right-click the catalog, click Properties, and select the Fields tab. Then enter the additional fields as you would for any other table (see ‘Creating feature classes and tables’ earlier in this chapter).

You can also perform searches to query the raster catalog. You might do this to find only rasters of a specific date or having a low percentage of cloud cover on an image. You can search by geography to view only those rasters that coincide with your area of interest. (See ‘Searching for data and maps’ earlier in this chapter.)

The input rasters are stored as individual datasets within the raster catalog—you can access the properties for a dataset by right-clicking it.

When you preview the table for the raster catalog you can see that each raster dataset is stored as a record in the table. You can add fields to the table, such as the creation date, the source, and so on, to manage the raster datasets more efficiently.

After creating the empty raster catalog, right-click it, point to Load, and click Load Data. Browse to the rasters to add, and add them to the list.

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Using ArcGIS Desktop

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In addition to the basic geodatabase data types of feature classes, tables, and rasters, you can extend your geodatabase with datasets that are used for specific applications, such as surface modeling and analysis; modeling the flow of people, goods, or resources over networks; or locating features or incidents along a street or highway network. Usually, these datasets are built from feature classes and tables that already exist in your geodatabase. While this section describes how to define these datasets in your geodatabase, Chapter 3, ‘Data Compilation and Editing’, contains information on how to create and edit the features that the datasets contain.

Creating a terrain dataset for surface modelingA terrain dataset is used to model surfaces using TIN structures within a geodatabase (see also ‘Creating a TIN surface’ in Chapter 5). Terrains are also used to manage massive 3D point collections—for example, billion point LiDAR collections. You define and build the terrain dataset from existing feature classes stored in a feature dataset. You can also specify scales at which to display the terrain at a lower resolution, so it will draw faster.

Adding specialized datasets to a geodatabase

Specify how the feature classes will be used for building the Terrain (or accept the defaults).

Specify the number of pyramid levels. Pyramids are used to draw the Terrain more quickly (but with lower resolution) when zoomed out.

The final panel summarizes the settings—click Finish to build the Terrain (or Back to make changes).

Select the feature classes that will be used to build the Terrain. These include spot elevations, contour lines, and breaklines (such as streams or graded roadbeds).

To create a Terrain, right-click the feature dataset containing the feature classes that will be used to build the surface, point to New, and click Terrain.

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