com.vividsolutions.jts.index.bintree

Class Bintree

java.lang.Object

com.vividsolutions.jts.index.bintree.Bintree

public class Bintree
extends Object

An BinTree (or "Binary Interval Tree") is a 1-dimensional version of a quadtree. It indexes 1-dimensional intervals (which may be the projection of 2-D objects on an axis). It supports range searching (where the range may be a single point). This structure is dynamic - new items can be added at any time, and it will support deletion of items (although this is not currently implemented).

This implementation does not require specifying the extent of the inserted items beforehand. It will automatically expand to accomodate any extent of dataset.

The bintree structure is used to provide a primary filter for interval queries. The query() method returns a list of all objects which may intersect the query interval. Note that it may return objects which do not in fact intersect. A secondary filter is required to test for exact intersection. Of course, this secondary filter may consist of other tests besides intersection, such as testing other kinds of spatial relationships.

This index is different to the Interval Tree of Edelsbrunner or the Segment Tree of Bentley.

Version:

1.7

Constructor Summary

Constructors

Constructor and Description
Bintree()

Method Summary

Methods

Modifier and Type	Method and Description
int	depth()
static Interval	ensureExtent(Interval itemInterval, double minExtent) Ensure that the Interval for the inserted item has non-zero extents.
void	insert(Interval itemInterval, Object item)
Iterator	iterator()
int	nodeSize() Compute the total number of nodes in the tree
List	query(double x)
List	query(Interval interval) Queries the tree to find all candidate items which may overlap the query interval.
void	query(Interval interval, Collection foundItems) Adds items in the tree which potentially overlap the query interval to the given collection.
boolean	remove(Interval itemInterval, Object item) Removes a single item from the tree.
int	size()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Bintree

public Bintree()

Method Detail

ensureExtent

public static Interval ensureExtent(Interval itemInterval,
                    double minExtent)

Ensure that the Interval for the inserted item has non-zero extents. Use the current minExtent to pad it, if necessary

depth

public int depth()

size

public int size()

nodeSize

public int nodeSize()

Compute the total number of nodes in the tree

Returns:

the number of nodes in the tree

insert

public void insert(Interval itemInterval,
          Object item)

remove

public boolean remove(Interval itemInterval,
             Object item)

Removes a single item from the tree.

Parameters:

itemEnv - the Envelope of the item to be removed

item - the item to remove

Returns:

true if the item was found (and thus removed)

iterator

public Iterator iterator()

query

public List query(double x)

query

public List query(Interval interval)

Queries the tree to find all candidate items which may overlap the query interval. If the query interval is null, all items in the tree are found. min and max may be the same value

query

public void query(Interval interval,
         Collection foundItems)

Adds items in the tree which potentially overlap the query interval to the given collection. If the query interval is null, add all items in the tree.

Parameters:

interval - a query nterval, or null

resultItems - the candidate items found