基于GeoTools，给定一条多段线，计算并获取从起点开始500米处的点坐标

可以使用以下代码基于GeoTools，给定一条多段线，计算并获取从起点开始500米处的点坐标：

import org.geotools.data.FeatureSource;
import org.geotools.data.shapefile.ShapefileDataStore;
import org.geotools.data.shapefile.ShapefileDataStoreFactory;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.factory.CommonFactoryFinder;
import org.geotools.geometry.jts.JTSFactoryFinder;
import org.geotools.geometry.jts.JTSUtilities;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.referencing.CRS;
import org.geotools.referencing.GeodeticCalculator;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.geotools.styling.*;
import org.locationtech.jts.geom.*;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.filter.Filter;
import org.opengis.filter.FilterFactory2;
import org.opengis.filter.identity.FeatureId;

import java.io.File;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class GeoToolsLine500m {

    public static void main(String[] args) throws Exception {
        // 加载多段线
        File file = new File("line.shp");
        ShapefileDataStoreFactory factory = new ShapefileDataStoreFactory();
        ShapefileDataStore dataStore = (ShapefileDataStore) factory.createDataStore(file.toURI().toURL());
        dataStore.setCharset(org.geotools.data.shapefile.ShpFiles.UTF_8);
        String typeName = dataStore.getTypeNames()[0];
        FeatureSource<SimpleFeatureType, SimpleFeature> featureSource = dataStore.getFeatureSource(typeName);
        SimpleFeatureCollection featureCollection = featureSource.getFeatures();
        SimpleFeatureIterator featureIterator = featureCollection.features();

        // 获取FeatureCollection的坐标系
        CoordinateReferenceSystem crs = featureCollection.getSchema().getCoordinateReferenceSystem();

        // 创建GeometryFactory
        GeometryFactory geomFactory = JTSFactoryFinder.getGeometryFactory();
        // 创建GeodeticCalculator
        GeodeticCalculator calculator = new GeodeticCalculator(DefaultGeographicCRS.WGS84);

        // 遍历每个Feature
        while (featureIterator.hasNext()) {
            SimpleFeature feature = featureIterator.next();
            Geometry geometry = (Geometry) feature.getDefaultGeometry();

            // 遍历每个MultiLineString
            if (geometry instanceof MultiLineString) {
                MultiLineString multiLineString = (MultiLineString) geometry;
                for (int i = 0; i < multiLineString.getNumGeometries(); i++) {
                    LineString lineString = (LineString) multiLineString.getGeometryN(i);

                    // 计算每个LineString的起点
                    Coordinate startCoord = lineString.getCoordinateN(0);
                    Point startPoint = geomFactory.createPoint(startCoord);

                    // 设置计算起点
                    calculator.setStartingGeographicPoint(startCoord.x, startCoord.y);
                    // 计算距离起点500米的点坐标
                    calculator.setDirection(0, 500);
                    Point point500m = null;
                    try {
                        double[] dest = calculator.getDestinationPosition();
                        point500m = geomFactory.createPoint(new Coordinate(dest[0], dest[1]));
                    } catch (Exception e) {
                        e.printStackTrace();
                    }

                    // 将点坐标转换到FeatureCollection的坐标系
                    if (point500m != null) {
                        try {
                            MathTransform transform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, crs);
                            point500m = (Point) JTS.transform(point500m, transform);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }

                    // 输出点坐标
                    if (point500m != null) {
                        System.out.println("Lon: " + point500m.getX() + ", Lat: " + point500m.getY());
                    }
                }
            }
        }

        featureIterator.close();
        dataStore.dispose();
    }
}

需要注意的是，该代码使用的是WGS84坐标系，如果需要使用其他坐标系，需要修改代码中的相关部分。