Class QuadPrefixTree
- java.lang.Object
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- org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree
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- org.apache.lucene.spatial.prefix.tree.QuadPrefixTree
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- Direct Known Subclasses:
PackedQuadPrefixTree
public class QuadPrefixTree extends SpatialPrefixTree
ASpatialPrefixTreewhich uses a quad tree in which an indexed term will be generated for each cell, 'A', 'B', 'C', 'D'.- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static classQuadPrefixTree.FactoryFactory for creatingQuadPrefixTreeinstances with useful defaultsprotected classQuadPrefixTree.QuadCellindividual QuadPrefixTree grid cell
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Field Summary
Fields Modifier and Type Field Description static intDEFAULT_MAX_LEVELSdoublegridHprotected doublegridWstatic intMAX_LEVELS_POSSIBLEprotected booleanrobustprotected doublexmaxprotected doublexmidprotected doublexminprotected doubleymaxprotected doubleymidprotected doubleymin-
Fields inherited from class org.apache.lucene.spatial.prefix.tree.SpatialPrefixTree
ctx, maxLevels
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Constructor Summary
Constructors Constructor Description QuadPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx)QuadPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx, int maxLevels)QuadPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx, org.locationtech.spatial4j.shape.Rectangle bounds, int maxLevels)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected intbattenberg(double xmid, double ymid, double xp, double yp)Returns a Z-Order quadrant [0-3].protected voidcheckBattenbergNotRobustly(char c, double cx, double cy, int level, List<Cell> matches, BytesRef str, org.locationtech.spatial4j.shape.Shape shape, int maxLevel)CellgetCell(org.locationtech.spatial4j.shape.Point p, int level)Returns the cell containing pointpat the specifiedlevel.doublegetDistanceForLevel(int level)Given a cell having the specified level, returns the distance from opposite corners.intgetLevelForDistance(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).CellIteratorgetTreeCellIterator(org.locationtech.spatial4j.shape.Shape shape, int detailLevel)Gets the intersecting cells for the specified shape, without exceeding detail level.CellgetWorldCell()Returns the level 0 cell which encompasses all spatial data.voidprintInfo(PrintStream out)CellreadCell(BytesRef term, Cell scratch)This creates a new Cell (or re-usingscratchif 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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Field Detail
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MAX_LEVELS_POSSIBLE
public static final int MAX_LEVELS_POSSIBLE
- See Also:
- Constant Field Values
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DEFAULT_MAX_LEVELS
public static final int DEFAULT_MAX_LEVELS
- See Also:
- Constant Field Values
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xmin
protected final double xmin
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xmax
protected final double xmax
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ymin
protected final double ymin
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ymax
protected final double ymax
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xmid
protected final double xmid
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ymid
protected final double ymid
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gridW
protected final double gridW
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gridH
public final double gridH
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robust
protected boolean robust
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Constructor Detail
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QuadPrefixTree
public QuadPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx, org.locationtech.spatial4j.shape.Rectangle bounds, int maxLevels)
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QuadPrefixTree
public QuadPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx)
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QuadPrefixTree
public QuadPrefixTree(org.locationtech.spatial4j.context.SpatialContext ctx, int maxLevels)
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Method Detail
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getWorldCell
public Cell getWorldCell()
Description copied from class:SpatialPrefixTreeReturns the level 0 cell which encompasses all spatial data. Equivalent toSpatialPrefixTree.readCell(BytesRef,Cell)with no bytes.- Specified by:
getWorldCellin classSpatialPrefixTree
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printInfo
public void printInfo(PrintStream out)
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getLevelForDistance
public int getLevelForDistance(double dist)
Description copied from class:SpatialPrefixTreeReturns the level of the largest grid in which its longest side is less than or equal to the provided distance (in degrees). Consequentlydistacts 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:
getLevelForDistancein classSpatialPrefixTree- Parameters:
dist->= 0- Returns:
- level [1 to maxLevels]
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getCell
public Cell getCell(org.locationtech.spatial4j.shape.Point p, int level)
Returns the cell containing pointpat the specifiedlevel.
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checkBattenbergNotRobustly
protected void checkBattenbergNotRobustly(char c, double cx, double cy, int level, List<Cell> matches, BytesRef str, org.locationtech.spatial4j.shape.Shape shape, int maxLevel)
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battenberg
protected int battenberg(double xmid, double ymid, double xp, double yp)Returns a Z-Order quadrant [0-3].
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getDistanceForLevel
public double getDistanceForLevel(int level)
Description copied from class:SpatialPrefixTreeGiven 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:
getDistanceForLevelin classSpatialPrefixTree- Parameters:
level- [1 to maxLevels]- Returns:
> 0
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readCell
public Cell readCell(BytesRef term, Cell scratch)
Description copied from class:SpatialPrefixTreeThis creates a new Cell (or re-usingscratchif 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:
readCellin classSpatialPrefixTree
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getTreeCellIterator
public CellIterator getTreeCellIterator(org.locationtech.spatial4j.shape.Shape shape, int detailLevel)
Description copied from class:SpatialPrefixTreeGets 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:
getTreeCellIteratorin 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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