java将geojson转换为图片详细代码

以下是使用Java将GeoJSON转换为图片的详细代码：

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.util.List;
import javax.imageio.ImageIO;
import org.geojson.Feature;
import org.geojson.FeatureCollection;
import org.geojson.GeoJsonObject;
import org.geojson.LngLatAlt;
import org.geojson.Point;
import org.geojson.Polygon;
import org.geojson.jackson.JsonParser;
import org.geojson.jackson.ObjectMapper;


public class GeoJsonToImage {

    public static void main(String[] args) throws Exception {
        // 读取GeoJSON文件
        FileInputStream fis = new FileInputStream(new File("input.geojson"));
        ObjectMapper mapper = new ObjectMapper();
        JsonParser parser = new JsonParser(mapper);
        FeatureCollection featureCollection = parser.parseFeatureCollection(fis);

        // 计算GeoJSON数据的范围
        double minX = Double.POSITIVE_INFINITY;
        double minY = Double.POSITIVE_INFINITY;
        double maxX = Double.NEGATIVE_INFINITY;
        double maxY = Double.NEGATIVE_INFINITY;
        for (Feature feature : featureCollection.getFeatures()) {
            GeoJsonObject geometry = feature.getGeometry();
            if (geometry instanceof Point) {
                LngLatAlt coordinates = ((Point) geometry).getCoordinates();
                minX = Math.min(minX, coordinates.getLongitude());
                minY = Math.min(minY, coordinates.getLatitude());
                maxX = Math.max(maxX, coordinates.getLongitude());
                maxY = Math.max(maxY, coordinates.getLatitude());
            } else if (geometry instanceof Polygon) {
                List<List<LngLatAlt>> coordinates = ((Polygon) geometry).getCoordinates();
                for (List<LngLatAlt> ring : coordinates) {
                    for (LngLatAlt point : ring) {
                        minX = Math.min(minX, point.getLongitude());
                        minY = Math.min(minY, point.getLatitude());
                        maxX = Math.max(maxX, point.getLongitude());
                        maxY = Math.max(maxY, point.getLatitude());
                    }
                }
            }
        }

        // 计算图片的大小和比例
        int width = 800;
        int height = (int) (800 * (maxY - minY) / (maxX - minX));
        double xRatio = width / (maxX - minX);
        double yRatio = height / (maxY - minY);

        // 创建图片
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2d = image.createGraphics();
        g2d.setBackground(Color.WHITE);
        g2d.clearRect(0, 0, width, height);

        // 绘制GeoJSON数据
        for (Feature feature : featureCollection.getFeatures()) {
            GeoJsonObject geometry = feature.getGeometry();
            if (geometry instanceof Point) {
                LngLatAlt coordinates = ((Point) geometry).getCoordinates();
                int x = (int) ((coordinates.getLongitude() - minX) * xRatio);
                int y = (int) ((maxY - coordinates.getLatitude()) * yRatio);
                g2d.setColor(Color.RED);
                g2d.fillRect(x - 5, y - 5, 10, 10);
            } else if (geometry instanceof Polygon) {
                List<List<LngLatAlt>> coordinates = ((Polygon) geometry).getCoordinates();
                for (List<LngLatAlt> ring : coordinates) {
                    int[] xPoints = new int[ring.size()];
                    int[] yPoints = new int[ring.size()];
                    for (int i = 0; i < ring.size(); i++) {
                        LngLatAlt point = ring.get(i);
                        int x = (int) ((point.getLongitude() - minX) * xRatio);
                        int y = (int) ((maxY - point.getLatitude()) * yRatio);
                        xPoints[i] = x;
                        yPoints[i] = y;
                    }
                    g2d.setColor(Color.GREEN);
                    g2d.fillPolygon(xPoints, yPoints, ring.size());
                }
            }
        }

        // 保存图片
        ImageIO.write(image, "png", new File("output.png"));

        // 关闭流
        fis.close();
    }

}

这个程序使用 `org.geojson` 包解析 GeoJSON 数据，绘制点和多边形，并保存为 PNG 图片。你可以替换 `org.geojson` 包为其它 GeoJSON 解析库，以适应你的需求。