Coverages

Each library is divided into a number of Coverages, which may be reference coverages or thematic coverages. Each coverage is a grouping of data of broadly similar physical nature, regardless of its data type. Thus separate coverages exist for example for hydrography, transportation and vegetation.

The table below shows the relationship between the libraries and the coverages. Note that not all coverages will necessarily exist within a given area. For example, most of the feature classes in the vegetation coverage are currently implemented only in the NOAMER dataset.

Library	Coverage	Coverage Type	Coverage name
Reference Library	Library Reference	Reference	libref
	Database Reference	Reference	dbref
	Political Entities	Reference	polbnd
	Place Names	Reference	placenam
Data Libraries	Library Reference	Reference	libref
	Tile Reference	Reference	tileref
	Boundaries	Thematic	bnd
	Data Quality	Thematic	dq
	Elevation	Thematic	elev
	Hydrography	Thematic	hydro
	Industry	Thematic	ind
	Physiography	Thematic	phys
	Population	Thematic	pop
	Transportation	Thematic	trans
	Utilities	Thematic	util
	Vegetation	Thematic	veg

Feature Classes