Java 如何在geoTools中使用GeometricShapeFactory在地图上创建圆

我目前正在使用下面的代码创建GeoJson多边形。这给了我一个无效的坏循环

在这种情况下，半径=1609.34，以米为单位为1英里

        public  GeoJsonPolygon createRadiusPolygon(  Point point,double RADIUS) {       

              GeometricShapeFactory shapeFactory = new GeometricShapeFactory();
              shapeFactory.setNumPoints(32);
              shapeFactory.setCentre(new com.vividsolutions.jts.geom.Coordinate(point.getX(), point.getY()));
              shapeFactory.setSize(RADIUS * 2);
              com.vividsolutions.jts.geom.Geometry circle = shapeFactory.createCircle();
              List<Point> points = new ArrayList<Point>();
                for (com.vividsolutions.jts.geom.Coordinate coordinate : circle.getCoordinates()) {
                    Point lngLatAtl = new Point(coordinate.x, coordinate.y);
                    points.add(lngLatAtl);
                }
                Collections.reverse(points);
                return new GeoJsonPolygon(points);
            }

---

…

您的输出圆是有效的，它恰好超过了地球表面的直径，因此您的GIS在绘制它时可能会遇到问题！问题是你不分青红皂白地混合了度数和米数，而GeoTools根本不知道你想要它做什么

您需要向程序中添加一些有关点坐标参考系的信息，如果该投影是地理投影，即以度为单位，则将问题转换为以米为单位的投影

public Geometry bufferPoint(Measure<Double, Length> distance, CoordinateReferenceSystem origCRS, Geometry geom) {
    Geometry pGeom = geom;
    MathTransform toTransform, fromTransform = null;
    // reproject the geometry to a local projection
    Unit<Length> unit = distance.getUnit();
    if (!(origCRS instanceof ProjectedCRS)) {

      double x = geom.getCoordinate().x;
      double y = geom.getCoordinate().y;

      String code = "AUTO:42001," + x + "," + y;
      // System.out.println(code);
      CoordinateReferenceSystem auto;
      try {
        auto = CRS.decode(code);
        toTransform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, auto);
        fromTransform = CRS.findMathTransform(auto, DefaultGeographicCRS.WGS84);
        pGeom = JTS.transform(geom, toTransform);
        unit = SI.METER;
      } catch (MismatchedDimensionException | TransformException | FactoryException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }

    } else {
      unit = (Unit<Length>) origCRS.getCoordinateSystem().getAxis(0).getUnit();

    }


    // buffer
    Geometry out = pGeom.buffer(distance.doubleValue(unit));
    Geometry retGeom = out;
    // reproject the geometry to the original projection
    if (!(origCRS instanceof ProjectedCRS)) {
      try {
        retGeom = JTS.transform(out, fromTransform);

      } catch (MismatchedDimensionException | TransformException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
    return retGeom;
  }

---

您的输出圆是有效的，它刚好超过地球表面的直径，因此您的GIS可能在绘制它时遇到问题！问题是你不分青红皂白地混合了度数和米数，而GeoTools根本不知道你想要它做什么

您需要向程序中添加一些有关点坐标参考系的信息，如果该投影是地理投影，即以度为单位，则将问题转换为以米为单位的投影

public Geometry bufferPoint(Measure<Double, Length> distance, CoordinateReferenceSystem origCRS, Geometry geom) {
    Geometry pGeom = geom;
    MathTransform toTransform, fromTransform = null;
    // reproject the geometry to a local projection
    Unit<Length> unit = distance.getUnit();
    if (!(origCRS instanceof ProjectedCRS)) {

      double x = geom.getCoordinate().x;
      double y = geom.getCoordinate().y;

      String code = "AUTO:42001," + x + "," + y;
      // System.out.println(code);
      CoordinateReferenceSystem auto;
      try {
        auto = CRS.decode(code);
        toTransform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, auto);
        fromTransform = CRS.findMathTransform(auto, DefaultGeographicCRS.WGS84);
        pGeom = JTS.transform(geom, toTransform);
        unit = SI.METER;
      } catch (MismatchedDimensionException | TransformException | FactoryException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }

    } else {
      unit = (Unit<Length>) origCRS.getCoordinateSystem().getAxis(0).getUnit();

    }


    // buffer
    Geometry out = pGeom.buffer(distance.doubleValue(unit));
    Geometry retGeom = out;
    // reproject the geometry to the original projection
    if (!(origCRS instanceof ProjectedCRS)) {
      try {
        retGeom = JTS.transform(out, fromTransform);

      } catch (MismatchedDimensionException | TransformException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
    return retGeom;
  }

---

谢谢@iant。。您用于获取输出的“距离”是否以米为单位？……在OP中。如果需要，该方法的实施要点是什么？JTS点@-73.87,40.84，CRS是CRS。DecodePSG:4326；对于Measure？，您是否可以剪切并粘贴此方法“调用”的代码行：Measure dist=Measure.value1.0，NonSI.MILE；版本18-SNAPSHOT，但应适用于所有最新版本谢谢@iant。。您用于获取输出的“距离”是否以米为单位？……在OP中。如果需要，该方法的实施要点是什么？JTS点@-73.87,40.84，CRS是CRS。DecodePSG:4326；对于Measure？，您是否可以剪切并粘贴此方法“调用”的代码行：Measure dist=Measure.value1.0，NonSI.MILE；版本18-SNAPSHOT，但应适用于所有最新版本。请注意，如果您使用的是来自JTS com.livitsolutions.JTS.geom或org.locationtech.JTS.geom的坐标类，那么X对应于经度，Y对应于纬度。在上面的帖子中，你需要像这样交换参数：新的坐标系，纬度这救了我的命！请注意，如果您使用的是来自JTS com.livitsolutions.JTS.geom或org.locationtech.JTS.geom的坐标类，那么X对应于经度，Y对应于纬度。在上面的帖子中，你需要像这样交换参数：新的坐标系，纬度这救了我的命！

//Measure<Double, Length> dist = Measure.valueOf(50.0, SI.KILOMETER);
Measure<Double, Length> dist = Measure.valueOf(1.0, NonSI.MILE);
GeometryFactory gf = new GeometryFactory();
Point p = gf.createPoint(new Coordinate(-73.87,40.84));
buf.bufferPoint(dist, DefaultGeographicCRS.WGS84, p);

    double latitude = 40.689234d;
    double longitude = -74.044598d;
    double diameterInMeters = 2000d; //2km

    GeometricShapeFactory shapeFactory = new GeometricShapeFactory();
    shapeFactory.setNumPoints(64); // adjustable
    shapeFactory.setCentre(new Coordinate(latitude, longitude));
    // Length in meters of 1° of latitude = always 111.32 km
    shapeFactory.setWidth(diameterInMeters/111320d);
    // Length in meters of 1° of longitude = 40075 km * cos( latitude ) / 360
    shapeFactory.setHeight(diameterInMeters / (40075000 * Math.cos(Math.toRadians(latitude)) / 360));

    Polygon circle = shapeFactory.createEllipse();