坐标转换-使用geotools读取和转换地理空间表的坐标系（sqlserver、postgresql）

前言：

业务上通过GIS软件将空间数据导入到数据库时，因为不同的数据来源和软件设置，可能导入到数据库的空间表坐标系是各种各样的。
如果要把数据库空间表发布到geoserver并且统一坐标系，只是在geoserver单纯的设置坐标系只是改了定义并没有实际执行坐标转换，所以需要在数据库层面统一好坐标系，再发布到geoserver。
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1,开发前准备

1.1,数据准备

要准备测试数据，可以参考地理空间表的导入。
我这里使用arcgis pro导入sqlserver，如果导入postgresql需要企业数据库才行，也就是需要离线证书，比较麻烦。
我先导入一个4524的投影坐标，测试转换为4490
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1.2,环境准备

坐标转换需要先读取数据库的空间表原坐标系，在根据原坐标系转换为目标坐标系。
使用的转换工具是geotool。
pom引入必要的依赖，geotools版本是24.3

<dependency>
    <groupId>org.geotools</groupId>
    <artifactId>gt-main</artifactId>
    <version>${geotools.version}</version>
</dependency>
<dependency>
     <groupId>org.geotools</groupId>
     <artifactId>gt-jdbc</artifactId>
     <version>${geotools.version}</version>
 </dependency>
 <dependency>
     <groupId>org.geotools.jdbc</groupId>
     <artifactId>gt-jdbc-sqlserver</artifactId>
     <version>${geotools.version}</version>
 </dependency>
 <dependency>
     <groupId>org.geotools.jdbc</groupId>
     <artifactId>gt-jdbc-postgis</artifactId>
     <version>${geotools.version}</version>
 </dependency>

2,读取空间表原坐标系

要使用geotool读取空间表的坐标系，需要先使用geotool提供的方法创建DataStore,官网有一个示例代码
https://docs.geotools.org/latest/userguide/library/jdbc/sqlserver.html

java.util.Map params = new java.util.HashMap();
params.put( "dbtype", "sqlserver");   //（巨坑）
params.put( "host", "localhost");
params.put( "port", 4866);
params.put( "user", "geotools");
params.put( "passwd", "geotools");
DataStore dataStore=DataStoreFinder.getDataStore(params);

这是一个坑，官方说明是版本14之后支持Microsoft JDBC driver，dbtype应该就不需要使用jtds前缀了，实际上不加必报错

先写一个测试方法，传入数据库连接信息，表名，数据库类型，返回原表坐标系

import org.geotools.data.DataStore;
import org.geotools.data.DataStoreFinder;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.jdbc.JDBCDataStoreFactory;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.referencing.crs.CoordinateReferenceSystem;

public static int getEpsg(DatabaseConfig databaseConfig, String tableName) {
        DataStore dataStore = null;
        try {
            Map<String, Object> params = new HashMap<>();
//        params.put(JDBCDataStoreFactory.SCHEMA.key, "dbo");
           if (DatabaseType.SQLSERVER.equals(databaseConfig.getDatabaseType())) {
                params.put(JDBCDataStoreFactory.DBTYPE.key, "jtds-sqlserver");
            } else {
                params.put(JDBCDataStoreFactory.DBTYPE.key, "jtds-postgis");
            }
            params.put(JDBCDataStoreFactory.HOST.key, databaseConfig.getHost());
            params.put(JDBCDataStoreFactory.PORT.key, databaseConfig.getPort());
            params.put(JDBCDataStoreFactory.DATABASE.key, databaseConfig.getDatabaseName());
            params.put(JDBCDataStoreFactory.USER.key, databaseConfig.getUsername());
            params.put(JDBCDataStoreFactory.PASSWD.key, databaseConfig.getPassword());
            dataStore = DataStoreFinder.getDataStore(params);
            if (dataStore == null) {
                System.out.println("Failed to connect to the database.");
                return -1;
            }
            // Get the feature source for the "aa" table
            SimpleFeatureSource featureSource = dataStore.getFeatureSource(tableName);
            // Get the feature type and its CRS
            SimpleFeatureType featureType = featureSource.getSchema();
            CoordinateReferenceSystem crs = featureType.getCoordinateReferenceSystem();
            // Print the CRS details
            if (crs != null) {
                System.out.println("Spatial Reference System: " + crs.getName());
                System.out.println("EPSG Code: " + crs.getName().getCode());
                System.out.println("crs : " + crs.toString());
                //抽取原表坐标系
                int result = extractEPSG(crs.toString());
                System.out.println("Result: " + result);
                return result;
            }
            // Close the data store
            dataStore.dispose();
            return 0;
        } catch (IOException e) {
            log.error("查询空间表坐标系异常：{}", e.toString());
            return -1;
        } finally {
            if (dataStore != null) {
                dataStore.dispose();
            }
        }
    }

然后看一下解析出来坐标信息

Spatial Reference System: EPSG:CGCS2000 / 3-degree Gauss-Kruger zone 36
EPSG Code: CGCS2000 / 3-degree Gauss-Kruger zone 36
crs : PROJCS["CGCS2000 / 3-degree Gauss-Kruger zone 36", 
  GEOGCS["China Geodetic Coordinate System 2000", 
    DATUM["China 2000", 
      SPHEROID["CGCS2000", 6378137.0, 298.257222101, AUTHORITY["EPSG","1024"]], 
      AUTHORITY["EPSG","1043"]], 
    PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], 
    UNIT["degree", 0.017453292519943295], 
    AXIS["Geodetic latitude", NORTH], 
    AXIS["Geodetic longitude", EAST], 
    AUTHORITY["EPSG","4490"]], 
  PROJECTION["Transverse_Mercator", AUTHORITY["EPSG","9807"]], 
  PARAMETER["central_meridian", 108.0], 
  PARAMETER["latitude_of_origin", 0.0], 
  PARAMETER["scale_factor", 1.0], 
  PARAMETER["false_easting", 36500000.0], 
  PARAMETER["false_northing", 0.0], 
  UNIT["m", 1.0], 
  AXIS["Northing", NORTH], 
  AXIS["Easting", EAST], 
  AUTHORITY["EPSG","4524"]]

我想要的是之前我们在arcgis pro中看到的投影坐标，位于crs信息的最后一个EPSG内，针对crs信息写一个方法解析出epsg

    public static int extractEPSG(String input) {
        Pattern pattern = Pattern.compile("AUTHORITY\\[\"EPSG\",\"(\\d+)\"\\]");
        Matcher matcher = pattern.matcher(input);

        int lastEPSG = 0;
        while (matcher.find()) {
            lastEPSG = Integer.parseInt(matcher.group(1));
        }
        return lastEPSG;
    }

3,执行坐标转换

我这里目标坐标系写死，因为系统需要插入到sqlserver中的都要统一坐标系，所以直接在原表更新了。
如果要保留原表信息可以复制表在副本表更新坐标。
sqlserver与postgresql中空间函数有些差异，需要区分处理。

/**
     * 地理空间表坐标转换
     *
     * @param sourceEpsg     原表坐标系
     * @param config         数据库连接信息
     * @param tableName      表名  dbo.ROAD
     * @param geometryColumn 空间字段
     */
    public static void epsgTo4490(int sourceEpsg, DatabaseConfig config, String tableName, String geometryColumn) {
        String sourceEPSG = "EPSG:" + sourceEpsg;
        String targetEPSG = "EPSG:4490";
        ResultSet resultSet = null;
        try (Connection connection = DatabaseConnection.getConnection(config)) {
            //拼接sql
            String sql;
            if (config.getDatabaseType().SQLSERVER.equals(config.getDatabaseType())) {
                sql = "SELECT " + geometryColumn + ".STAsText() as Shape,OBJECTID FROM " + tableName;
            } else {
                //ST_AsText(columns)
                sql = "SELECT ST_AsText(" + geometryColumn + ") as Shape,OBJECTID FROM " + tableName;
            }

            // 使用连接执行 SQL 查询操作
            PreparedStatement statement = connection.prepareStatement(sql);
            resultSet = statement.executeQuery();

            // Create MathTransform
            CRSFactory crsFactory = new CRSFactory();
            org.osgeo.proj4j.CoordinateReferenceSystem sourceCRS = crsFactory.createFromName(sourceEPSG);
            org.osgeo.proj4j.CoordinateReferenceSystem targetCRS = crsFactory.createFromName(targetEPSG);
            CoordinateTransformFactory transformFactory = new CoordinateTransformFactory();
            CoordinateTransform transform = transformFactory.createTransform(sourceCRS, targetCRS);

            // Process each row of the result set
            while (resultSet.next()) {
                String shape = resultSet.getString("Shape");
                int objectId = resultSet.getInt("OBJECTID");

                // Convert the string representation of the geometry to a JTS Geometry object
                WKTReader reader = new WKTReader();
                Geometry geometry = reader.read(shape);

                // Perform the coordinate transformation for each coordinate in the geometry
                for (int i = 0; i < geometry.getCoordinates().length; i++) {
                    Coordinate srcCoord = geometry.getCoordinates()[i];
                    ProjCoordinate targetCoord = new ProjCoordinate(srcCoord.getX(), srcCoord.getY());
                    transform.transform(targetCoord, targetCoord); // 将源坐标转换为目标坐标，并保存在 targetCoord 中
                    srcCoord.setX(targetCoord.x);
                    srcCoord.setY(targetCoord.y);
                }

                // Convert the transformed geometry back to a string
                WKTWriter writer = new WKTWriter();
                String transformedShape = writer.write(geometry);

                // Update the original table with the transformed geometry using the primary key
                String updateSQL;
                if (DatabaseType.SQLSERVER.equals(config.getDatabaseType())) {
                    updateSQL = "UPDATE " + tableName + " SET " + geometryColumn + " = ? WHERE OBJECTID = ?";
                } else {
                    //UPDATE "public"."ROAD" SET Shape = ST_SetSRID(ST_GeomFromText("Shape"), 4490);
                    updateSQL = "UPDATE " + tableName + " SET " + geometryColumn + " = ST_SetSRID(?,4490) WHERE OBJECTID = ?";
                }
                statement = connection.prepareStatement(updateSQL);
                statement.setString(1, transformedShape);
                statement.setInt(2, objectId);
                statement.executeUpdate();
                statement.clearParameters();
            }
            if (DatabaseType.SQLSERVER.equals(config.getDatabaseType())) {
                //修复多边形错误   UPDATE dbo.ROAD SET Shape = Shape.MakeValid()
                String updateSQL = "UPDATE " + tableName + " SET " + geometryColumn + " = " + geometryColumn + ".MakeValid()";
                statement = connection.prepareStatement(updateSQL);
                statement.executeUpdate();
                //指定坐标系 UPDATE dbo.ROAD SET Shape.STSrid=4490
                updateSQL = "UPDATE " + tableName + " SET " + geometryColumn + ".STSrid=4490";
                statement = connection.prepareStatement(updateSQL);
                statement.executeUpdate();
            }
            // Close the resources
            statement.close();
            resultSet.close();
        } catch (SQLException e) {
            log.error("坐标转换中sql执行异常：{}", e.getMessage());
        } catch (ParseException e) {
            log.error("坐标转换中异常：{}", e.getMessage());
        }
    }

上述代码只是sqlservcer亲测多种坐标系转换正常，且转换后的表发布到geoserver和arcgis都能正常预览且聚焦位置正确，postgresql还有待测试

4,单元测试

    public static void main(String[] args) throws SQLException {
        String tableName = "ROAD";
        //测试sqlserver
        DatabaseConfig databaseConfig = new DatabaseConfig(DatabaseType.SQLSERVER, "127.0.0.1", 1433, "测试中文数据库", "sa", "xxxx");
        //测试postgresql
        //DatabaseConfig databaseConfig = new DatabaseConfig(DatabaseType.POSTGRESQL, "127.0.0.1", 5432, "postgis20", "postgres", "xxxxxxx");
        int sourceEpsg = TableEpsgUtil.getEpsg(databaseConfig, tableName);
        System.out.println("原表坐标：" + sourceEpsg);
        //如果获取到原表坐标并且不是4490,则执行转换
        if (sourceEpsg > 0 && sourceEpsg != 4490) {
            epsgTo4490(sourceEpsg, databaseConfig, tableName, "Shape");
            System.out.println("坐标转换完成");
        }
    }