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

package org.apache.lucene.spatial.prefix.tree
This package is about SpatialPrefixTree and any supporting classes. A SpatialPrefixTree 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/

Related Packages
Package
Description
org.apache.lucene.spatial.prefix
Prefix Tree Strategy.
Class
Description
Cell
Represents a grid cell.
CellCanPrune
Grid cells that share nothing with other cells when calling `Cell.getNextLevelCells(Shape)` might implement this interface.
CellIterator
An Iterator of SpatialPrefixTree Cells.
DateRangePrefixTree
A PrefixTree for date ranges in which the levels of the tree occur at natural periods of time (e.g.
GeohashPrefixTree
A `SpatialPrefixTree` based on Geohashes.
GeohashPrefixTree.Factory
Factory for creating `GeohashPrefixTree` instances with useful defaults
LegacyCell
The base for the original two SPT's: Geohash and Quad.
NumberRangePrefixTree
A SpatialPrefixTree for single-dimensional numbers and number ranges of fixed precision values (not floating point).
NumberRangePrefixTree.NRShape
Base interface for `Shape`s this prefix tree supports.
NumberRangePrefixTree.UnitNRShape
A unit value Shape implemented as a stack of numbers, one for each level in the prefix tree.
PackedQuadPrefixTree
Uses a compact binary representation of 8 bytes to encode a spatial quad trie.
PackedQuadPrefixTree.Factory
Factory for creating `PackedQuadPrefixTree` instances with useful defaults.
QuadPrefixTree
A `SpatialPrefixTree` which uses a quad tree in which an indexed term will be generated for each cell, 'A', 'B', 'C', 'D'.
QuadPrefixTree.Factory
Factory for creating `QuadPrefixTree` instances with useful defaults
S2PrefixTree
Spatial prefix tree for S2 Geometry.
S2PrefixTree.Factory
Factory for creating `S2PrefixTree` instances with useful defaults
S2ShapeFactory
Shape factory for Spatial contexts that support S2 geometry.
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.