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
ASpatialPrefixTree
which 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 class
QuadPrefixTree.Factory
Factory for creatingQuadPrefixTree
instances with useful defaultsprotected class
QuadPrefixTree.QuadCell
individual QuadPrefixTree grid cell
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Field Summary
Fields Modifier and Type Field Description static int
DEFAULT_MAX_LEVELS
double
gridH
protected double
gridW
static int
MAX_LEVELS_POSSIBLE
protected boolean
robust
protected double
xmax
protected double
xmid
protected double
xmin
protected double
ymax
protected double
ymid
protected double
ymin
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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 int
battenberg(double xmid, double ymid, double xp, double yp)
Returns a Z-Order quadrant [0-3].protected void
checkBattenbergNotRobustly(char c, double cx, double cy, int level, List<Cell> matches, BytesRef str, org.locationtech.spatial4j.shape.Shape shape, int maxLevel)
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).CellIterator
getTreeCellIterator(org.locationtech.spatial4j.shape.Shape shape, int detailLevel)
Gets the intersecting cells for the specified shape, without exceeding detail level.Cell
getWorldCell()
Returns the level 0 cell which encompasses all spatial data.void
printInfo(PrintStream out)
Cell
readCell(BytesRef term, Cell scratch)
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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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: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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printInfo
public void printInfo(PrintStream out)
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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
public Cell getCell(org.locationtech.spatial4j.shape.Point p, int level)
Returns the cell containing pointp
at 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: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
public Cell readCell(BytesRef term, Cell scratch)
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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