[Geotools-gt2-users] different results when transforming point from EPSG:31251 -> EPSG:31287 with 14.3 and 21.2

[Clemens Eisserer]

Hi,

After upgrading an application from geotools-14.3 to 21.2 I've
observed strange behaviour when transforming points from one CRS
(EPSG:31251) to another (EPSG:31287).
The original code we had dies with an exception, however even two
other tries return different results from what I got with 14.3.
With an external tool I also get results which are identical to what
14.3 returns.

With 14.3 all 3 tries succeed and return the expected result:
> OldWay: POINT (259878.57433310486 377178.60575377225)
> Plain: GeneralDirectPosition[259878.57433310486, 377178.60575377225]
> JTS: POINT (259878.57433310486 377178.60575377225)

With 21.2 the geometryBuilder-based way fails, the two others return
consistent but different (wrong?) results:
> Plain: GeneralDirectPosition[219916.12907210115, 405574.2553041743]
> JTS: POINT (219916.12907210115 405574.2553041743)
> java.lang.IllegalArgumentException: DirectPosition cannot have a null CRS
>    at 
> org.geotools.geometry.jts.spatialschema.geometry.DirectPositionImpl.setCRS(DirectPositionImpl.java:155)
>    at 
> org.geotools.geometry.jts.spatialschema.geometry.DirectPositionImpl.<init>(DirectPositionImpl.java:125)
>    at 
> org.geotools.geometry.jts.spatialschema.geometry.primitive.PrimitiveFactoryImpl.createDirectPosition(PrimitiveFactoryImpl.java:95)
>    at 
> org.geotools.geometry.jts.spatialschema.geometry.primitive.PrimitiveFactoryImpl.createPoint(PrimitiveFactoryImpl.java:103)
>    at 
> org.geotools.geometry.GeometryBuilder.createPoint(GeometryBuilder.java:352)
>    at 
> org.geotools.geometry.GeometryBuilder.createPoint(GeometryBuilder.java:320)

Any idea whats going on here?

Best regards, Clemens


public class CoordinateTransformTest {

    @Test
    public void testTransform() throws FactoryException, TransformException {
        CoordinateReferenceSystem gkCRS = CRS.decode("EPSG:31251");
        CoordinateReferenceSystem dbCRS = CRS.decode("EPSG:31287");

        MathTransform transform = CRS.findMathTransform(gkCRS, dbCRS, true);
        DirectPosition2D pos2D = new DirectPosition2D(86765.44, 238436.25);

        DirectPosition posTransformed = transform.transform(pos2D, null);
        System.out.println("Plain: "+posTransformed);

        Point transformedPoint = (Point)
JTS.transform(JTS.toGeometry(pos2D.getDirectPosition()), transform);
        System.out.println("JTS: "+transformedPoint);
    }

    @Test
    public void testOldWay()  throws FactoryException, TransformException  {
        CoordinateReferenceSystem gkCRS = CRS.decode("EPSG:31251");
        CoordinateReferenceSystem dbCRS = CRS.decode("EPSG:31287");

        GeometryBuilder geometryBuilder = new GeometryBuilder(gkCRS);

        org.opengis.geometry.primitive.Point point =
geometryBuilder.createPoint(86765.44, 238436.25);

        MathTransform mtf = CRS.findMathTransform(gkCRS, dbCRS, true);

        Point transformedPoint = (Point)
JTS.transform(JTS.toGeometry(point.getDirectPosition()), mtf);
        System.out.println("OldWay: "+transformedPoint);
    }
}


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