西安80地理坐标转wgs84坐标（两种方法）

方法一：

用proj4j(proj4对应的java库）towgs84参数对应的七个值为七参数值

public CoordinateTransform coordtrans() {

        CRSFactory targetFactory = new CRSFactory();
        CRSFactory crsFactory = new CRSFactory();
        //目标坐标系统
        String target_param =  "+proj=longlat +datum=WGS84 +no_defs ";
        CoordinateReferenceSystem target = targetFactory.createFromParameters("wgs84", target_param);
        //源坐标系统
        String xian80_param = "+proj=longlat +a=6378140 +b=6356755.288157528 +towgs84=115.8,-154.4,-82.3,0,0,0,8 +no_defs ";
        CoordinateReferenceSystem xian80 = crsFactory.createFromParameters("xian80", xian80_param);

        CoordinateTransformFactory ctf = new CoordinateTransformFactory();
        CoordinateTransform transform = ctf.createTransform(xian80, target);
        return transform;
    }

public static void main(String[] args) {

        SpringApplication.run(Demo1Application.class, args);
        Project_54 project_54=new  Project_54();
        CoordinateTransform transforms=project_54.coordtrans();

            if (transforms != null) {
                ProjCoordinate projCoordinate = new ProjCoordinate(121.976469682,41.4470288037);
                transforms.transform(projCoordinate, projCoordinate);
                Double dNorth = projCoordinate.y;
                Double dEast = projCoordinate.x;
                System.out.print(dNorth);
                System.out.print("/");
               System.out.print(dEast);

            }
    }

方法二：

用arcgis js api   steps.wkt参见https://developers.arcgis.com/java/10-2/guide/datum-transformations.htm#ESRI_SECTION1_7635FE2A60E6449898D5AD0ADE2CA0C，可以对wkt的七参数进行自定义调整。

 var steps= new GeographicTransformationStep() ;
        steps.wkt="GEOGTRAN[\"Xian_1980_To_WGS_1984\","+
        "GEOGCS[\"GCS_Xian_1980\",DATUM[\"D_Xian_1980\",SPHEROID[\"Xian_1980\",6378140.0,298.257]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],"+
        "GEOGCS[\"GCS_WGS_1984\",DATUM[\"D_WGS_1984\",SPHEROID[\"WGS_1984\",6378137.0,298.257223563]],PRIMEM[\"Greenwich\",0.0],UNIT[\"Degree\",0.0174532925199433]],"+
        "METHOD[\"Position_Vector\"],PARAMETER[\"X_Axis_Translation\",115.8],PARAMETER[\"Y_Axis_Translation\",-154.4],PARAMETER[\"Z_Axis_Translation\",-82.3],PARAMETER[\"X_Axis_Rotation\",0.0],PARAMETER[\"Y_Axis_Rotation\",0.0],PARAMETER[\"Z_Axis_Rotation\",0.0],PARAMETER[\"Scale_Difference\",8]]";
        var geographicTransformation=new GeographicTransformation({
            steps:[steps]
        })
        var inSpatialReference = new SpatialReference({
            wkid: 4610 //Sphere_Sinusoidal
           });
        var outSpatialReference = new SpatialReference({
            wkid: 4326
        });
        var wgsPoints=new Point([121.976469682,41.4470288037],inSpatialReference);
        console.log(wgsPoints)
        projection.load().then(function(){
            var projectedPoints = projection.project(wgsPoints, outSpatialReference,geographicTransformation);
          console.log(projectedPoints.x)
          console.log(projectedPoints.y) 
        })

总结：经证明，两种方法得出的结果是一样的

方法1结果：

方法二结果：