https://github.com/codingmiao/neo4j-rtree
a spatial index for neo4j 4.x
https://github.com/codingmiao/neo4j-rtree
neo4j rtree spatial-index
Last synced: 7 months ago
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a spatial index for neo4j 4.x
- Host: GitHub
- URL: https://github.com/codingmiao/neo4j-rtree
- Owner: codingmiao
- License: apache-2.0
- Created: 2020-05-28T13:55:02.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-11-06T10:05:12.000Z (over 1 year ago)
- Last Synced: 2025-08-02T10:58:02.550Z (7 months ago)
- Topics: neo4j, rtree, spatial-index
- Language: Java
- Size: 800 KB
- Stars: 8
- Watchers: 3
- Forks: 2
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# neo4j-rtree
一个基于neo4j构建的n维度空间索引
github: https://github.com/codingmiao/neo4j-rtree
gitee: https://gitee.com/wowtools/neo4j-rtree
[中文文档](README.md) | [README](README_en.md)
## 简介
rtree，是一个计算n维空间内对象的位置关系、距离关系的索引。 很多前辈开源了各类rtree的在内存中的实现，但是，在大数据量的场景下，完全构建在内存中的rtree存在内存占用高，初始化时间长等问题。
因此，本项目参考[conversant/rtree](https://github.com/conversant/rtree) 的实现思路，将rtree构建在图数据库 [neo4j](https://github.com/neo4j/neo4j)
中， 形成了一个内存可控、可持久化的rtree索引项目。
(注意: 旧版本 [v1.x](https://github.com/codingmiao/neo4j-rtree/tree/v1.x)
版本基于 [neo4j spatial](https://github.com/neo4j-contrib/spatial) 构建，存在递归过多容易栈内存溢出、只能用于2维空间等问题，已不再进行功能性更新)
## 使用示例
### 索引数据的的增删改
~~~java
try(RtreeEditor rtreeEditor=RtreeEditor.create(db,2000,indexName)){
//构建一个RectNd对象，描述n维对象的最小外接矩形
RectNd rect2d = new RectNd(new PointNd(new double[]{xmin, ymin}), new PointNd(new double[]{xmax, ymax}));
//add
rtreeEditor.add(rect2d);
//remove、update方法类似
}
~~~
完整示例请参见 [测试用例](https://github.com/codingmiao/neo4j-rtree/blob/v2.x/src/test/java/org/wowtools/neo4j/rtree/RtreeEditorTest.java)
### 相交关系查询
查询索引中的对象是否与输入的n维矩形相交
~~~java
//构造输入矩形
PointNd p0 = new PointNd(new double[]{x0, y0});
PointNd p1 = new PointNd(new double[]{x1, y1});
RectNd inputRange = new RectNd(p0, p1);
try (Transaction tx = db.beginTx()) {
//构建一个RtreeIntersectsSearcher对象
RtreeIntersectsSearcher searcher = RtreeIntersectsSearcher.get(tx, indexName);
searcher.intersects(inputRange, tx, (dataNodeId)->{
//打印查询到的nodeId，也可以拿着id在neo4j中查询node更详细的信息
System.out.println(dataNodeId);
return false;
});
}
~~~
完整示例请参见 [测试用例](https://github.com/codingmiao/neo4j-rtree/blob/v2.x/src/test/java/org/wowtools/neo4j/rtree/RtreeEditorTest.java)
### 最邻近搜索
~~~java
//求距离点(x,y)距离最近的5个点点
double x = 0.5, y = 0.5;
int hitNum = 5;
try (Transaction tx = db.beginTx()) {
//构建一个RtreeNearestSearcher对象
RtreeNearestSearcher searcher = RtreeNearestSearcher.get(tx, indexName);
//构建查询条件NearestNeighbour，包括点PointNd、最大返回条数、距离计算公式
PointNd pt = new PointNd(new double[]{x, y});
NearestNeighbour nearestNeighbour = new NearestNeighbour(hitNum, pt) {
@Override
public DistanceResult createDistanceResult(PointNd pointNd, long dataNodeId) {
RectNd rectNd = ...;//根据dataNodeId从neo4j中查询dataNode的
double dist = dist(rectNd);//计算dataNode到(x,y)的距离
return new DistanceResult(dist, dataNodeId);
}
};
nearests = searcher.nearest(nearestNeighbour, tx);
}
...
//定义距离公式
private static final double dist(RectNd rect2d) {
double[] xy = rect2d.getMaxXs();
double x1 = xy[0];
double y1 = xy[1];
return Math.sqrt(Math.pow(x1 - x, 2) + Math.pow(y1 - y, 2));
}
~~~
完整示例请参见 [测试用例](https://github.com/codingmiao/neo4j-rtree/blob/v2.x/src/test/java/org/wowtools/neo4j/rtree/RtreeNearestSearcherTest.java)
### 基于jts geometry对象的二维索引
[geometry2d](https://github.com/codingmiao/neo4j-rtree/tree/v2.x/src/main/java/org/wowtools/neo4j/rtree/geometry2d) 是一个针对二维几何对象的特化包，同样也包含了上述功能，示例如下：
geometry2d 索引数据的的增删改 [Geometry2dRtreeEditor](https://github.com/codingmiao/neo4j-rtree/blob/v2.x/src/test/java/org/wowtools/neo4j/rtree/geometry2d/Geometry2dRtreeEditorTest.java)
geometry2d 相交关系查询 [Geometry2dRtreeIntersectsSearcher](https://github.com/codingmiao/neo4j-rtree/blob/v2.x/src/test/java/org/wowtools/neo4j/rtree/geometry2d/Geometry2dRtreeEditorTest.java)
geometry2d 最邻近搜索 [Geometry2dRtreeNearestSearcher](https://github.com/codingmiao/neo4j-rtree/blob/v2.x/src/test/java/org/wowtools/neo4j/rtree/geometry2d/Geometry2dRtreeNearestSearcherTest.java)
## install
引入maven依赖，最新版本号为2.0.2
```
org.wowtools
neo4j-rtree
${neo4j-rtree-version}
```
如果你的项目中已经使用了其它版本的neo4j(例如企业版)而引起冲突，可考虑exclusions:
```
org.wowtools
neo4j-rtree
${neo4j-rtree-version}
org.neo4j
neo4j-common
org.neo4j
neo4j
```
注意，maven中央库的依赖用jdk21编译，所以如果你的项目使用了jdk8或其它版本，你可能需要自己编译一份适合于你的jdk的:
clone & install
```
git clone https://github.com/codingmiao/neo4j-rtree.git
mvn clean install -DskipTests
```