A coverage is a collection of feature classes used to represent geographic phenomena. Each coverage is a directory stored as a series of files.
The set of features contained in a coverage depends on the type of geographic phenomena being modeled. The following table gives a brief description of the types of phenomena each feature class is used to model:
Coverage feature classes
|Feature class||Application and use||Examples|
Well sites, mountain peaks
Street sections, contours, streams, sewers, power lines, gas lines
Connecting points and endpoints of linear features
Valves on pipelines, intersections of streets, power poles, manhole covers
Streets, contours, stream networks, sewers, power line networks, gas line networks, street addresses
Defines route features
Street section, traffic lanes, pipe condition, above- and below-ground transmission lines
Soil units, land use, parcels, building footprints, forest stands, ownership
Area features, multiple polygons
Census geography, state of Hawaii, overlapping wildlife habitat
Street names, place-names on road maps
Geographic registration and control
Registration for digitizing
Rubber sheeting and adjustment
Edgematching map sheets, feature snapping, datum adjustments
Defines map extent
Rectangle describing outer boundary of coverage
Coverage feature class file description
|Feature class||Description||Attribute table name: <cover>.*|
A point defined by an x,y coordinate pair used to represent point features or assign User-IDs to polygons.
A line defined as a set of ordered x,y coordinates used to represent linear features and polygon boundaries.
The endpoints of an arc or the point at which two or more arcs connect.
A linear feature composed of one or more arcs or parts of arcs.
An arc or portion of an arc used to define a route or the building blocks of routes.
An area defined by the arcs that make up its boundary, including arcs defining any islands inside. User-IDs are assigned to label points.
A collection of one or more contiguous or noncontiguous polygons defining a geographic feature.
A text string describing a geographic feature. Shape points are used to position and draw annotation.
A geographic reference or control point used to register and transform the coordinates in a coverage.