Coverages

Coverages are a file-based data format native to ESRI's ArcInfo® Workstation software. Conceptually, coverages can be thought of as a combination of other vector data formats you have learned about.

Like a feature class, coverages have a geometry type of point, line, or polygon. And, also like a feature class, a coverage represents a single thematic layer, such as schools, streets, or land use, in which all features have the same attributes and are located within a common geographic area.

On the other hand, coverages are like a geodatabase feature dataset because they store a set of spatially related feature classes. Point, line, and polygon coverages each contain a different set of feature classes that, together, define their features.

 

ArcCatalog view of a point, line, and polygon coverage

 

The geometry type of the coverage determines which feature classes it will store.

 

More information More about coverage feature classes

Coverages are a common data format, and you may come across them in your organization or on the Internet. While there are many, the main coverage feature classes are point, arc, polygon, label, and tic.

·  The point feature class stores the point features of a point coverage.

·  The arc feature class stores the line features of a line coverage or the polygon boundaries of a polygon coverage.

·  The polygon feature class stores the polygon features of a polygon coverage.

·  The label feature class stores points in the center of each polygon of a polygon coverage—these points can be used to place feature labels.

·  The tic feature class stores geographic control points that represent known real-world coordinates. Tics are used to reference coverage features to the real world. All coverages have a tic feature class.

Coverages can contain many more types of feature classes, including annotation, routes, and regions. For more information about coverages and their feature classes, refer to the ArcGIS Desktop Help (Contents tab -> ArcCatalog -> Working with coverages).

 

The attributes and spatial relationships associated with a coverage feature class are stored in INFO-format tables. INFO tables are stored in a folder called info, which is stored with the other coverage files in a workspace folder. Even if there is more than one coverage in a workspace folder, there is always only one info folder that contains the INFO tables for all the coverages in that workspace.

 

Windows Explorer view of three coverages

 

Here you see how coverages display in Windows Explorer. The Coverages workspace folder contains three coverages: landuse, schools, and streets. The info folder contains the INFO tables associated with each of those coverages

 

By default, in the ArcCatalog™ Catalog tree, you won't see the info folder associated with a coverage, but you can see it in your operating system's file manager (e.g., Windows Explorer). You should never move, copy, rename, or delete a coverage using your operating system's file manager since the connection between the coverage feature classes and the info folder could become broken or corrupted. Always use ArcCatalog to manage coverages.