java - 使用JAVA中的geotools在定义的距离(km)内从一条线(GPS坐标)生成多边形

Question

使用地理工具是否可以在定义的距离内从一条线(坐标[])生成多边形？例如。 (100,100)、(101,100)、(102,100)，距离 1 公里。因此，它从每个点生成一个圆并成为某物。像:

--------------之前

(========)之后

或者我必须首先将 GPS 坐标转换为以公里为单位的正交坐标，然后使用三角函数生成多边形，最后将其转换回 GPS？

Answer 1

最简单的是，您只需调用底层 JTS 几何图形上的 buffer(distance) 方法即可。棘手的一点是处理以米为单位的投影的重投影(因此您可以以米或公里为单位指定缓冲区)。

public SimpleFeature bufferFeature(SimpleFeature feature,
        Measure<Double, Length> distance) {
    // extract the geometry
    GeometryAttribute gProp = feature.getDefaultGeometryProperty();
    CoordinateReferenceSystem origCRS = gProp.getDescriptor()
        .getCoordinateReferenceSystem();

    Geometry geom = (Geometry) feature.getDefaultGeometry();
    Geometry pGeom = geom;
    MathTransform toTransform,fromTransform = null;
    // reproject the geometry to a local projection
    if (!(origCRS instanceof ProjectedCRS)) {

        Point c = geom.getCentroid();
        double x = c.getCoordinate().x;
        double y = c.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);
        } catch (MismatchedDimensionException | TransformException
            | FactoryException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }

    }

    // buffer
    Geometry out = buffer(pGeom, distance.doubleValue(SI.METER));
    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 a new feature containing the geom
    SimpleFeatureType schema = feature.getFeatureType();
    SimpleFeatureTypeBuilder ftBuilder = new SimpleFeatureTypeBuilder();
    ftBuilder.setCRS(origCRS);
    //ftBuilder.setDefaultGeometry("buffer");
    ftBuilder.addAll(schema.getAttributeDescriptors());
    ftBuilder.setName(schema.getName());

    SimpleFeatureType nSchema = ftBuilder.buildFeatureType();
    SimpleFeatureBuilder builder = new SimpleFeatureBuilder(nSchema);
     List<Object> atts = feature.getAttributes();
     for(int i=0;i<atts.size();i++) {
         if(atts.get(i) instanceof Geometry) {
         atts.set(i, retGeom);
         }
     }
    SimpleFeature nFeature = builder.buildFeature(null, atts.toArray() );
    return nFeature;
    }

完整代码位于https://gist.github.com/ianturton/9a7cfee378e7072ec3cd它展示了如何处理整个事情。