思路都是google上找的

思路1：效果不是很好，勉强可以

/** *   reference:http://stackoverflow.com/questions/25495560/how-can-i-find-the-best-place-to-fit-a-label-inside-a-polygon *   refernce:https://www.mapbox.com/blog/polygon-center/ *  1.Create four polygons by translating the original one with w, -w, h, -h where w and h are the semi-width and semi-height of the label.    2.Intersect those four polygons.    3.if the intersection is null - the label won't fit in the polygon. Exit.    4.All points inside the intersection satisfy the requirement: place the center of the label in one of those points. * @param polygon * @return */static public Geometry getPolygonVisualPoint(Polygon polygon){    Coordinate[] coordinates  = polygon.getCoordinates();    List<Coordinate> leftCoordinateList = Arrays.asList(deepCopy(coordinates));    List<Coordinate> rightCoordinateList = Arrays.asList(deepCopy(coordinates));    List<Coordinate> topCoordinateList = Arrays.asList(deepCopy(coordinates));    List<Coordinate> bottomCoordinateList = Arrays.asList(deepCopy(coordinates));

    Envelope envelope = polygon.getEnvelopeInternal();    double h = envelope.getHeight();    double w = envelope.getWidth();

    double minSize = Math.min(h,w)/2;

    translateCoord(leftCoordinateList,true,minSize*-1);    translateCoord(rightCoordinateList,true,minSize*1);    translateCoord(topCoordinateList,false,minSize*1);    translateCoord(bottomCoordinateList,false,minSize*-1);

    Polygon leftPolygon = createPolygon(leftCoordinateList);    Polygon rightPolygon = createPolygon(rightCoordinateList);    Polygon topPolygon = createPolygon(topCoordinateList);    Polygon bottomPolygon = createPolygon(bottomCoordinateList);

    List<Geometry> polygons = new ArrayList<>();    polygons.add(polygon);    polygons.add(leftPolygon);    polygons.add(rightPolygon);    polygons.add(topPolygon);    polygons.add(bottomPolygon);

    Geometry geometry = intersect(polygons);    return geometry;}

static public Geometry intersect(List<Geometry> geoms){    Geometry intersectRes = geoms.get(0);    for(int i=1;i<geoms.size();i++){        if(intersectRes.intersects(geoms.get(i))){            intersectRes = intersectRes.intersection(geoms.get(i));        }    }    return intersectRes;}static private Coordinate[] deepCopy(Coordinate[] arr){    Coordinate[] dest = new Coordinate[arr.length];    int i=0;    for(Coordinate coordinate : arr){        dest[i++] = (Coordinate) coordinate.clone();    }    return dest;}static public Polygon createPolygon(List<Coordinate> list){    Coordinate[] arr = new Coordinate[list.size()];    list.toArray(arr);    return createPolygon(arr);}static public Polygon createPolygon(Coordinate[] coordinates){    GeometryFactory geometryFactory = new GeometryFactory();    Polygon polygon = geometryFactory.createPolygon(geometryFactory.createLinearRing(coordinates),null);    return polygon;}static private void translateCoord(List<Coordinate> coordinates,boolean isX,double delta){    for(Coordinate coordinate : coordinates){        if(isX){            coordinate.x += delta;        }else {            coordinate.y += delta;        }    }}

思路2http://stackoverflow.com/questions/4279478/largest-circle-inside-a-non-convex-polygonhttps://github.com/mapbox/polylabel/blob/master/polylabel.js--这里有使用的demo，重点是求中心时注意设置精度，如果单位是经纬度，建议0.001https://github.com/mourner/tinyqueue/blob/master/index.js--tinyquene