判断一个点是否在多边形上,GIS里经常要用的功能,但在平面几何上也是可用的。
这里借助大名鼎鼎的geotools实现
jar包依赖,pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.wisely</groupId> <artifactId>point</artifactId> <version>1.0-SNAPSHOT</version> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <geotools.version>13.1</geotools.version> </properties> <dependencies> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-geojson</artifactId> <version>${geotools.version}</version> </dependency> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-geometry</artifactId> <version>${geotools.version}</version> </dependency> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-epsg-hsql</artifactId> <version>${geotools.version}</version> </dependency> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-jts-wrapper</artifactId> <version>${geotools.version}</version> </dependency> </dependencies> <repositories> <repository> <id>maven2-repository.dev.java.net</id> <name>Java.net repository</name> <url>http://download.java.net/maven/2</url> </repository> <repository> <id>osgeo</id> <name>Open Source Geospatial Foundation Repository</name> <url>http://download.osgeo.org/webdav/geotools/</url> </repository> </repositories> </project>
代码
String wktPoly = "POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10))"; //请自行搜素了解wkt格式 String wktPoint = "POINT (30 30)"; WKTReader reader = new WKTReader(JTSFactoryFinder.getGeometryFactory()); GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(null); Geometry point = reader.read(wktPoint); Geometry poly = reader.read(wktPoly); poly.contains(point); //返回true或false