# Package org.apache.lucene.spatial.prefix.tree

The Spatial Prefix package supports spatial indexing by index-time tokens where adding characters to a string gives greater resolution.

See: Description

Class Summary
Class | Description
--- | ---
GeohashPrefixTree | A `SpatialPrefixTree` based on Geohashes.
GeohashPrefixTree.Factory | Factory for creating `GeohashPrefixTree` instances with useful defaults
Node | Represents a grid cell.
QuadPrefixTree | A `SpatialPrefixTree` which uses a quad tree in which an indexed term will be generated for each node, 'A', 'B', 'C', 'D'.
QuadPrefixTree.Factory | Factory for creating `QuadPrefixTree` instances with useful defaults
SpatialPrefixTree | A spatial Prefix Tree, or Trie, which decomposes shapes into prefixed strings at variable lengths corresponding to variable precision.
SpatialPrefixTreeFactory | Abstract Factory for creating `SpatialPrefixTree` instances with useful defaults and passed on configurations defined in a Map.

## Package org.apache.lucene.spatial.prefix.tree Description

The Spatial Prefix package supports spatial indexing by index-time tokens where adding characters to a string gives greater resolution.

Potential Implementations include:

- http://en.wikipedia.org/wiki/Quadtree
- http://en.wikipedia.org/wiki/Geohash
- http://healpix.jpl.nasa.gov/