I wrote ST_Project following the same syntax as hive esri spatial function, but the result is the not exactly the same

[fragrantic]

import org.apache.hadoop.hive.ql.exec.UDF; import org.apache.hadoop.io.BytesWritable; import org.apache.hadoop.hive.serde2.io.DoubleWritable; import com.esri.core.geometry.ogc.OGCGeometry; import com.esri.core.geometry.ogc.OGCPoint; import com.esri.hadoop.hive.GeometryUtils; import com.esri.core.geometry.Point;

public class ST_Project extends UDF { final DoubleWritable resultDouble = new DoubleWritable();

static double EARTH_RADIUS = 6378137.0;

static double degToRad(double deg) {
    return (deg * Math.PI) / 180.0;
}

static double radToDeg(double rad) {
    return (rad * 180.0) / Math.PI;
}

static double x;
static double y;

public static BytesWritable evaluate(BytesWritable geom, double distance, double bearing) {

    if (geom == null) {
        return null;
    }

    try {

    double angular = distance / EARTH_RADIUS;
    double bearingRad = degToRad(bearing);
    OGCGeometry Geometry = GeometryUtils.geometryFromEsriShape(geom);
    OGCPoint pt1 = (OGCPoint)Geometry;      
    double latRad = degToRad(((OGCPoint) pt1).X());
    double lonRad = degToRad(((OGCPoint) pt1).Y());
    double a = Math.sin((latRad));
    double b = Math.cos((angular));
    double c = Math.cos((latRad));
    double d = Math.sin((angular));
    double e = Math.cos((bearingRad));

    double lat = Math.asin(((a * b) + (c * d * e)));

    double f = Math.sin((bearingRad));
    double h = Math.sin((lat));
    double i = (f * d * c);
    double j = (b - (a * h));

    double lon = lonRad + Math.atan2(i, j);

    x = radToDeg(lon);
    y = radToDeg(lat);

    DoubleWritable x1 = new DoubleWritable(x);
    DoubleWritable y1 = new DoubleWritable(y);

    Point stPt = new Point(y1.get(),x1.get());

    BytesWritable ret = GeometryUtils.geometryToEsriShapeBytesWritable(OGCGeometry.createFromEsriGeometry(stPt, null));

    return ret;
    } catch (Exception e) {
        return null;} } }

[randallwhitman]

On what input? What is the expected result? What is the actual result?

[fragrantic]

If you are familiar white postgis which is a spatial extension of postgres, it comes with a lot of spatial function one of them being ST_Project, ST_Project — Returns a POINT projected from a start point using a distance in meters and bearing (azimuth) in radians. Now if I were to execute this function like this : select st_astext(st_project(st_point(0,0), 100000, radians(45))) I get this as a result: Point(0.63523085373227,0.6351918164606) And if you were to do the same thing in postgres I get this : Point(0.635231029125537,0.639472334729198)

[randallwhitman]

The code posted in the description on 05/14 appears to have calculations for a sphere, which is a fast approximation, but not entirely accurate, for an oblate spheroid such as the Earth.

[fragrantic]

So what am I supposed to do ?

[randallwhitman]

If the question is how to use a Geometry API to apply a geodesic displacement, you might try asking under the Esri Geometry API for Java or at a general programming Q&A forum.

[fragrantic]

Thank you I will do so

[randallwhitman]

https://github.com/Esri/geometry-api-java/issues/175