C# Class Lucene.Net.Spatial.Prefix.Tree.SpatialPrefixTree

A Spatial Prefix Tree, or Trie, which decomposes shapes into prefixed strings at variable lengths corresponding to variable precision. Each string corresponds to a spatial region. Implementations of this class should be thread-safe and immutable once initialized.

ファイルを表示 Open project: apache/lucenenet Class Usage Examples

Protected Properties

Property	Type	Description
ctx	Spatial4n.Core.Context.SpatialContext
maxLevels	int

Public Methods

Method	Description
GetCell ( byte bytes, int offset, int len ) : Cell
GetCell ( byte bytes, int offset, int len, Cell target ) : Cell
GetCell ( string token ) : Cell	The cell for the specified token. The cell for the specified token. The empty string should be equal to WorldCell. Precondition: Never called when token length > maxLevel.
GetCells ( IPoint p, int detailLevel, bool inclParents ) : IList	A Point-optimized implementation of GetCells(Shape, int, bool, bool). That method in facts calls this for points. This implementation depends on GetCell(string) being fast, as its called repeatedly when incPlarents is true.
GetCells ( IShape shape, int detailLevel, bool inclParents, bool simplify ) : IList	Gets the intersecting cells for the specified shape, without exceeding detail level. Gets the intersecting cells for the specified shape, without exceeding detail level. If a cell is within the query shape then it's marked as a leaf and none of its children are added. This implementation checks if shape is a IPoint and if so returns GetCells(Point, int, bool).
GetDistanceForLevel ( int level ) : double	Given a cell having the specified level, returns the distance from opposite corners. Given a cell having the specified level, returns the distance from opposite corners. Since this might very depending on where the cell is, this method may over-estimate.
GetLevelForDistance ( double dist ) : int	Returns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees). Returns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees). Consequently dist acts as an error epsilon declaring the amount of detail needed in the grid, such that you can get a grid with just the right amount of precision.
SpatialPrefixTree ( SpatialContext ctx, int maxLevels ) : Spatial4n.Core.Context
ToString ( ) : string

Protected Methods

Method	Description
GetCell ( IPoint p, int level ) : Cell	Returns the cell containing point p at the specified level.

Private Methods

Method	Description
CellsToTokenStrings ( ICollection cells ) : IList
RecursiveGetCells ( Cell cell, IShape shape, int detailLevel, bool inclParents, bool simplify, IList result ) : bool	Returns true if cell was added as a leaf. Returns true if cell was added as a leaf. If it wasn't it recursively descends.

Method Details

GetCell() protected method

Returns the cell containing point p at the specified level.

protected GetCell ( IPoint p, int level ) : Cell
p	IPoint
level	int
return	Cell

GetCell() public abstract method

public abstract GetCell ( byte bytes, int offset, int len ) : Cell
bytes	byte
offset	int
len	int
return	Cell

GetCell() public method

public GetCell ( byte bytes, int offset, int len, Cell target ) : Cell
bytes	byte
offset	int
len	int
target	Cell
return	Cell

GetCell() public abstract method

The cell for the specified token.

The cell for the specified token. The empty string should be equal to WorldCell. Precondition: Never called when token length > maxLevel.

public abstract GetCell ( string token ) : Cell
token	string
return	Cell

GetCells() public method

A Point-optimized implementation of GetCells(Shape, int, bool, bool). That method in facts calls this for points. This implementation depends on GetCell(string) being fast, as its called repeatedly when incPlarents is true.

public GetCells ( IPoint p, int detailLevel, bool inclParents ) : IList
p	IPoint
detailLevel	int
inclParents	bool
return	IList

GetCells() public method

Gets the intersecting cells for the specified shape, without exceeding detail level.

Gets the intersecting cells for the specified shape, without exceeding detail level. If a cell is within the query shape then it's marked as a leaf and none of its children are added. This implementation checks if shape is a IPoint and if so returns GetCells(Point, int, bool).

public GetCells ( IShape shape, int detailLevel, bool inclParents, bool simplify ) : IList
shape	IShape	the shape; non-null
detailLevel	int	the maximum detail level to get cells for
inclParents	bool	/// if true then all parent cells of leaves are returned /// too. The top world cell is never returned. ///
simplify	bool	/// for non-point shapes, this will simply/aggregate sets of /// complete leaves in a cell to its parent, resulting in /// ~20-25% fewer cells. ///
return	IList

GetDistanceForLevel() public method

Given a cell having the specified level, returns the distance from opposite corners.

Given a cell having the specified level, returns the distance from opposite corners. Since this might very depending on where the cell is, this method may over-estimate.

public GetDistanceForLevel ( int level ) : double
level	int	[1 to maxLevels]
return	double

GetLevelForDistance() public abstract method

Returns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees).

Returns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees). Consequently dist acts as an error epsilon declaring the amount of detail needed in the grid, such that you can get a grid with just the right amount of precision.

public abstract GetLevelForDistance ( double dist ) : int
dist	double	>= 0
return	int

SpatialPrefixTree() public method

public SpatialPrefixTree ( SpatialContext ctx, int maxLevels ) : Spatial4n.Core.Context
ctx	Spatial4n.Core.Context.SpatialContext
maxLevels	int
return	Spatial4n.Core.Context

ToString() public method

public ToString ( ) : string
return	string

Property Details

ctx protected_oe property

protected SpatialContext,Spatial4n.Core.Context ctx
return	Spatial4n.Core.Context.SpatialContext

maxLevels protected_oe property

protected int maxLevels
return	int