covering

func AllAncestors ¶

func AllAncestors(quadKeys []quadtree.QuadKey, minZoom byte) ([]quadtree.QuadKey, error)

func ExteriorCovering ¶

func ExteriorCovering(g geom.Geometry, maxTiles int) ([]quadtree.QuadKey, error)

ExteriorCovering returns a set of QuadKeys that approximates a Geometry with no more than maxTiles keys. The covering fully covers the geometry, but may also include some area outside it.

func SearchRanges ¶

func SearchRanges(quadKeys []quadtree.QuadKey, minZoom byte) ([]quadtree.QuadKeyRange, error)

SearchRanges takes a set of QuadKeys and returns a sorted list of ranges that contain all of those tiles and any of their descendants.

Note: these ranges also find a small number of keys outside those tiles (see the note in QuadKey.Range()). Use QuadKey.IsAncestorOf() to filter those out of the results.