试验GPT写一段postgis的两空间图层相交运算的java代码算法
写一段postgis的两空间图层相交运算的java代码算法
回答
2023/4/22 下午5:38:48
以下是一段基于PostGIS进行两空间图层相交运算的Java代码。这里以多边形为例。
import org.postgresql.util.PGobject;
import org.postgis.Geometry;
import org.postgis.PGgeometry;
import org.postgis.Polygon;
import java.sql.*;
public class SpatialIntersection {
public static void main(String[] args) {
try (Connection connection = DriverManager.getConnection("jdbc:postgresql://localhost:5432/mydb", "postgres", "mypassword")) {
// 连接数据库
Statement statement = connection.createStatement();
// 创建geometry类型表
statement.executeUpdate("CREATE TABLE IF NOT EXISTS states(id SERIAL PRIMARY KEY, state_name VARCHAR(50), state_geom geometry)");
statement.executeUpdate("CREATE TABLE IF NOT EXISTS cities(id SERIAL PRIMARY KEY, city_name VARCHAR(50), city_geom geometry)");
// 插入数据
String stateName1 = "California";
Polygon stateGeom1 = new Polygon(
new org.postgis.Point[]{
new org.postgis.Point(-124, 42),
new org.postgis.Point(-114, 42),
new org.postgis.Point(-114, 32),
new org.postgis.Point(-124, 32)
}
);
String stateName2 = "Nevada";
Polygon stateGeom2 = new Polygon(
new org.postgis.Point[]{
new org.postgis.Point(-119, 42),
new org.postgis.Point(-114, 42),
new org.postgis.Point(-114, 36),
new org.postgis.Point(-119, 36)
}
);
statement.executeUpdate("INSERT INTO states(state_name, state_geom) VALUES ('" + stateName1 + "', '"
+ toPGgeometryString(stateGeom1) + "');");
statement.executeUpdate("INSERT INTO states(state_name, state_geom) VALUES ('" + stateName2 + "', '"
+ toPGgeometryString(stateGeom2) + "');");
String cityName = "Los Angeles";
Polygon cityGeom = new Polygon(
new org.postgis.Point[]{
new org.postgis.Point(-118.5968, 34.281),
new org.postgis.Point(-118.4241, 34.3033),
new org.postgis.Point(-118.3258, 34.0506),
new org.postgis.Point(-118.4953, 34.0266),
new org.postgis.Point(-118.5968, 34.281)
}
);
statement.executeUpdate("INSERT INTO cities(city_name, city_geom) VALUES ('" + cityName + "', '"
+ toPGgeometryString(cityGeom) + "');");
// 进行空间相交计算
ResultSet resultSet = statement.executeQuery(
"SELECT state_name, city_name " +
"FROM states, cities " +
"WHERE ST_Intersects(states.state_geom, cities.city_geom)"
);
// 输出结果
while (resultSet.next()) {
String stateNameResult = resultSet.getString(1);
String cityNameResult = resultSet.getString(2);
System.out.println(stateNameResult + " contains " + cityNameResult);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
// 将Geometry对象转换为PGgeometry字符串
private static String toPGgeometryString(Geometry geom) throws SQLException {
PGgeometry pgGeom = new PGgeometry();
pgGeom.setGeometry(geom);
return new PGobject(pgGeom).getValue();
}
}
这段代码首先通过JDBC连接到PostgreSQL数据库,并在其中创建了两个geometry类型的表states
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