Class GeohashPrefixTree

A SpatialPrefixTree based on Geohashes. Uses Spatial4n.Util.GeohashUtils to do all the geohash work.

Note

This API is experimental and might change in incompatible ways in the next release.

Inheritance
object
SpatialPrefixTree
GeohashPrefixTree
Inherited Members
Namespace: Lucene.Net.Spatial.Prefix.Tree
Assembly: Lucene.Net.Spatial.dll
Syntax
public class GeohashPrefixTree : SpatialPrefixTree

Constructors

GeohashPrefixTree(SpatialContext, int)

Initializes a new instance of GeohashPrefixTree with the specified spatial context (ctx) and maxLevels.

Declaration
public GeohashPrefixTree(SpatialContext ctx, int maxLevels)
Parameters
Type Name Description
SpatialContext ctx

The spatial context.
int maxLevels

The maximum number of levels in the tree.
Exceptions
Type Condition
ArgumentNullException

ctx is null.
ArgumentOutOfRangeException

maxLevels is less than or equal to 0 or greater than MaxLevelsPossible.

Properties

MaxLevelsPossible

Any more than this and there's no point (double lat & lon are the same).

Declaration
public static int MaxLevelsPossible { get; }
Property Value
Type Description
int

Methods

GetCell(IPoint, int)

Returns the cell containing point p at the specified level.

Declaration
protected override Cell GetCell(IPoint p, int level)
Parameters
Type Name Description
IPoint p
int level
Returns
Type Description
Cell
Overrides

GetCell(byte[], int, int)

A SpatialPrefixTree based on Geohashes. Uses Spatial4n.Util.GeohashUtils to do all the geohash work.

Note

This API is experimental and might change in incompatible ways in the next release.

Declaration
public override Cell GetCell(byte[] bytes, int offset, int len)
Parameters
Type Name Description
byte[] bytes
int offset
int len
Returns
Type Description
Cell
Overrides

GetCell(string)

The cell for the specified token.

Declaration
public override Cell GetCell(string token)
Parameters
Type Name Description
string token
Returns
Type Description
Cell
Overrides
Remarks

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

GetLevelForDistance(double)

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

Declaration
public override int GetLevelForDistance(double dist)
Parameters
Type Name Description
double dist

= 0
Returns
Type Description
int

level [1 to maxLevels]
Overrides
Remarks

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.