Class GeohashPrefixTree
java.lang.Object
org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree
org.apache.lucene.spatial.prefix.tree.GeohashPrefixTree
- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
Modifier and TypeClassDescriptionstatic class
Factory for creatingGeohashPrefixTree
instances with useful defaults -
Field Summary
Fields inherited from class org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree
ctx, maxLevels
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Constructor Summary
ConstructorDescriptionGeohashPrefixTree
(org.locationtech.spatial4j.context.SpatialContext ctx, int maxLevels) -
Method Summary
Modifier and TypeMethodDescriptionprotected Cell
getCell
(org.locationtech.spatial4j.shape.Point p, int level) Returns the cell containing pointp
at the specifiedlevel
.double
getDistanceForLevel
(int level) Given a cell having the specified level, returns the distance from opposite corners.int
getLevelForDistance
(double dist) Returns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees).static int
Any more than this and there's no point (double lat and lon are the same).getTreeCellIterator
(org.locationtech.spatial4j.shape.Shape shape, int detailLevel) Gets the intersecting cells for the specified shape, without exceeding detail level.Returns the level 0 cell which encompasses all spatial data.This creates a new Cell (or re-usingscratch
if provided), initialized to the state as read by the bytes.Methods inherited from class org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree
getMaxLevels, getSpatialContext, toString
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Constructor Details
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GeohashPrefixTree
public GeohashPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx, int maxLevels)
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Method Details
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getMaxLevelsPossible
public static int getMaxLevelsPossible()Any more than this and there's no point (double lat and lon are the same). -
getWorldCell
Description copied from class:SpatialPrefixTree
Returns the level 0 cell which encompasses all spatial data. Equivalent toSpatialPrefixTree.readCell(BytesRef,Cell)
with no bytes.- Specified by:
getWorldCell
in classSpatialPrefixTree
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getLevelForDistance
public int getLevelForDistance(double dist) Description copied from class:SpatialPrefixTree
Returns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees). Consequentlydist
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.- Specified by:
getLevelForDistance
in classSpatialPrefixTree
- Parameters:
dist
->= 0
- Returns:
- level [1 to maxLevels]
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getCell
Returns the cell containing pointp
at the specifiedlevel
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getDistanceForLevel
public double getDistanceForLevel(int level) Description copied from class:SpatialPrefixTree
Given a cell having the specified level, returns the distance from opposite corners. Since this might vary depending on where the cell is, this method may over-estimate.- Specified by:
getDistanceForLevel
in classSpatialPrefixTree
- Parameters:
level
- [1 to maxLevels]- Returns:
> 0
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readCell
Description copied from class:SpatialPrefixTree
This creates a new Cell (or re-usingscratch
if provided), initialized to the state as read by the bytes. Warning: An implementation may refer to the same byte array (no copy). IfCell.setLeaf()
is subsequently called, it would then modify these bytes.- Specified by:
readCell
in classSpatialPrefixTree
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getTreeCellIterator
public CellIterator getTreeCellIterator(org.locationtech.spatial4j.shape.Shape shape, int detailLevel) Description copied from class:SpatialPrefixTree
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. For cells at detailLevel, they are marked as leaves too, unless it's a point.IMPORTANT: Cells returned from the iterator can be re-used for cells at the same level. So you can't simply iterate to subsequent cells and still refer to the former cell nor the bytes returned from the former cell, unless you know the former cell is a parent.
- Overrides:
getTreeCellIterator
in classSpatialPrefixTree
- Parameters:
shape
- the shape; possibly null but the caller should liberally callremove()
if so.detailLevel
- the maximum detail level to get cells for- Returns:
- the matching cells
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