分段相交: Mercator投影求nan值

Question

我对mercator投影有一点小问题，当我在纬度上投影时，我得到了nan值.

我的代码来自于这个问题：ConvertLATLONGTOXY

private static List<Point2D.Double> LatLongConvertionToXY(List<GeoPoint> coordinates) {
        List<Point2D.Double> xys = new ArrayList<Point2D.Double>();

        /*MercatorProjection projection = new MercatorProjection();*/
        Log.i("LATLONG2RAD", "Nouvelle conversion");
        for (GeoPoint coordinate : coordinates) {
            double latitude = Double.valueOf(coordinate.getLatitudeE6());
            double longitude = Double.valueOf(coordinate.getLongitudeE6());

            // convert to radian
            latitude = latitude * Math.PI / 180;
            longitude = longitude * Math.PI / 180;
            Log.i("LATLONG2RAD", String.valueOf(latitude)+" : "+String.valueOf(longitude));
            /*Point2D.Double d = projection.project(longitude,latitude,
                    new Point2D.Double());*/
            Point2D.Double d=new Point2D.Double();
            double QUARTERPI = Math.PI / 4.0;
            d.x = longitude;
            d.y = Math.log(Math.tan(QUARTERPI + 0.5 * latitude));
            Log.i("PointLATLONG YX", String.valueOf(d.y)+" : "+String.valueOf(d.x));
            xys.add(d);
        }

        return xys;
    }

返回值的示例: 12-15 21:42:27.165: I/LATLONG2RAD(32629)：Nouvelle转换

12-15 21:42:27.165: I/LATLONG2RAD(32629)：LAT 782581.6732236275 : LONG -10478.398323613315

12-15 21:42:27.165: I/LATLONG2RAD(32629)：LAT 782581.6732236275 : LONG -10478.398323613315

12-15 21:42:27.165: I/LATLONG2RAD(32629)：LAT 782587.2931838189 : LONG -10476.478461436123

12-15 21:42:27.165: I/LATLONG2RAD(32629)：LAT 782571.9517396939 : LONG -10476.478461436123

用于投影的返回值：

12-15 21:42:27.165: I/PointLATLONG YX(32629)：NaN：-10478.398323613315

12-15 21:42:27.165: I/PointLATLONG YX(32629)：NaN：-10478.398323613315

12-15 21:42:27.165: I/PointLATLONG YX(32629)：NaN：-10476.478461436123

12-15 21:42:27.165: I/PointLATLONG YX(32629)：1.7354151627839085：-10476.478461436123

Answer 1

最后，JRowan --没关系--我读了代码，然后用投影法mercator重试了，我发现我的问题--用osm geopoint -我的值第一个到nan值--我的值在微观上，而不是双倍的：

我的新代码：

private static List<Point2D.Double> LatLongConvertionToXY(List<GeoPoint> coordinates) {
        List<Point2D.Double> xys = new ArrayList<Point2D.Double>();

        MercatorProjection projection = new MercatorProjection();
        Log.i("LATLONG2RAD", "New");
        for (GeoPoint coordinate : coordinates) {
            double latitude = Double.valueOf(coordinate.getLatitudeE6());
            double longitude = Double.valueOf(coordinate.getLongitudeE6());

            //to decimal
            latitude=latitude / 1E6;
            longitude=longitude / 1E6;
            Log.i("LATLONG2RAD", "BEFORE RADIAN "+String.valueOf(latitude)+" : "+String.valueOf(longitude));
            //convert to radian
            latitude = latitude * Math.PI / 180;
            longitude = longitude * Math.PI / 180;
            //Log.i("LATLONG2RAD", String.valueOf(latitude)+" : "+String.valueOf(longitude));
            Point2D.Double d = projection.project(longitude,latitude,
                    new Point2D.Double());

            Log.i("LATLONG2RAD"," Y X "+ String.valueOf(d.y)+" : "+String.valueOf(d.x));
            xys.add(d);
        }

        return xys;
    }

这种预测似乎是好的：

12-15 22:41:40.257: I/LATLONG2RAD(1138)：y X 0.8505407464143129 : 0.11730010582132741

12-15 22:41:40.267: I/LATLONG2RAD(1138)：y X 0.8506068875926396 : 0.11715522604011937

12-15 22:41:40.267: I/LATLONG2RAD(1138)：y X 0.8505923208133851 : 0.1172139738227415

12-15 22:41:40.267: I/LATLONG2RAD(1138)：y X 0.8505727537288554 : 0.1172139738227415

但是现在另一个pb使用的是交集的计算：

public static GeoPoint intersectionV1bis(List<GeoPoint> mGeoPoints) {
        if (mGeoPoints.size() == 0 || mGeoPoints.size() > 4)
            return null;
        List<Point2D.Double> coordinates = LatLongConvertionToXY(mGeoPoints);
        double x1 = coordinates.get(0).x;
        double y1 = coordinates.get(0).y;
        double x2 = coordinates.get(1).x;
        double y2 = coordinates.get(1).y;
        double x3 = coordinates.get(2).x;
        double y3 = coordinates.get(2).y;
        double x4 = coordinates.get(3).x;
        double y4 = coordinates.get(3).y;
        double d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
        if (d == 0){
            Log.i("INTERSECT V1","Segments parallels");
            return null;
        }

        double xi = ((x3 - x4) * (x1 * y2 - y1 * x2) - (x1 - x2)
                * (x3 * y4 - y3 * x4))
                / d;
        double yi = ((y3 - y4) * (x1 * y2 - y1 * x2) - (y1 - y2)
                * (x3 * y4 - y3 * x4))
                / d;



        GeoPoint p = new GeoPoint(xi, yi);
        Log.i("INTERSECT","xi long"+String.valueOf(xi)+" : yi lat"+String.valueOf(yi));
        if (xi < Math.min(x1, x2) || xi > Math.max(x1, x2)){
            Log.i("INTERSECT V1","Not in segment 1");
            return null;
        }

        if (xi < Math.min(x3, x4) || xi > Math.max(x3, x4)){
            Log.i("INTERSECT V1","Not in segment 2");
            return null;
        }
        Log.i("INTERSECT","Intersection");
        return p;
    }

12-15 22:41:40.267: I/INTERSECT(1138)：xi 1138 0.11721397382272966:彝文0.8505800677870533

在开放的街道地图上，直线段相交，但代码拒绝，我不明白为什么。A点和B点是我最后和新的位置，C和D是点E的左右两个点(在第一个交叉点上按下按钮来定义当前位置的+90和-90 )，即在A和B之间。

我一直使用仿真器有相同的位置，但是当我试图计算A和B之间的第二次交叉时，E不是在C和D段上。