Cover provides static (a) methods to generate trixel covermaps of regions A covermap can be extracted as a list of trixels, or lists of HtmID (start, end) pairs. In the latter case, the HtmIDs are always for level 20 trixels. The trixels in the covermaps are either "inner" or "partial". Inner trixels are completely contained in the region. Partial trixels intersect the boundary of the region. Partial trixels follow the outline(s) of the region. The "outer" covermap is the union of "inner" and "partial" covermaps. Each covermap has an associated "cost," which is currently the number of (start, end) HtmID range pairs in the outer covermap. The cost is used in deciding when to terminate the generation of the covermap The Cover object uses an internal "machine" that does all the computing. The machine runs in stages, each successive step generates a finer resolution covermap and therefore increases the depth of the partial trixels in the covermap.

Hidranges manages lists of HtmID pairs. It is used mostly internally by the Cover class. It has public exposure, because the external test harness not in this namespace uses this class for verifying the internal workings of the HTM library

A singleton class housing many internal 'global' variables. Exposed only for its getVersion method

Trixel static methods operate on HtmID's mostly. operations needed to convert between location and HtmID several representations of a HtmID, and locations expressed in Cartesian, J2000 (ra/dec) geographic lat/lon space. Since functions in the Spherical assembly convert to and from J2000 or geographic coordinates, only XYZ is handled by this class

An augmented pair of HtmId values. Besides the low-high pair, it also includes a flag that indicates whether or not the trixels represented by the range are inner trixels.

A pair of low-high HtmId values

Markup is a classification of a trixel with respect to the way it intersects a region.