I have a Oracle database with spatial data in which coordinates are stored in RD format (srid 28992). To place them on a map (leaflet with openstreetmap) I need the coordinates in WGS84 (srid 4326) format.
I should be able to get the coordinates in that format by using SDO_CS.TRANSFORM. When I do that, all coordinates seems to be shifted eastwards by about 6m.
The verify that there was no problem with the data stored in the table, I created a query that takes RD coordinate 155000, 463000 and converts it to WGS84. From that query I get: 52,1551639130507 5,38735225721137
If I do the same transformation on op http://www.gpscoordinaten.nl/converteer-gps-coordinaten.php I get 52.15517, 5.38721 (which is the right coordinate)
The query used is this one:
SELECT
t.X,
t.Y
FROM
(
SELECT
SDO_CS.TRANSFORM( MDSYS.SDO_GEOMETRY( 2001, 28992, MDSYS.SDO_POINT_TYPE(
155000, 463000, NULL ), NULL, NULL ), 4326 ) AS geometry
FROM
dual
)
geo,
TABLE( SDO_UTIL.GETVERTICES( geo.geometry ) ) t;
Any idea why the conversion in Oracle is shifting the coordinates?
Have a look at this http://epsg.io/28992
PROJCS["Amersfoort / RD New",
GEOGCS["Amersfoort",
DATUM["Amersfoort",
SPHEROID["Bessel 1841",6377397.155,299.1528128,
AUTHORITY["EPSG","7004"]],
TOWGS84[565.417,50.3319,465.552,-0.398957,0.343988,-1.8774,4.0725],
AUTHORITY["EPSG","6289"]],
PRIMEM["Greenwich",0,
AUTHORITY["EPSG","8901"]],
UNIT["degree",0.0174532925199433,
AUTHORITY["EPSG","9122"]],
AUTHORITY["EPSG","4289"]],
PROJECTION["Oblique_Stereographic"],
PARAMETER["latitude_of_origin",52.15616055555555],
PARAMETER["central_meridian",5.38763888888889],
PARAMETER["scale_factor",0.9999079],
PARAMETER["false_easting",155000],
PARAMETER["false_northing",463000],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]],
AXIS["X",EAST],
AXIS["Y",NORTH],
AUTHORITY["EPSG","28992"]]
But for Oracle select wktext3d from cs_srs where srid = 28992; you get
PROJCS[ "Amersfoort / RD New",
GEOGCS["Amersfoort",
DATUM["Amersfoort",
SPHEROID[ "Bessel 1841", 6377397.155, 299.1528128,
AUTHORITY["EPSG", "7004"]],
TOWGS84[593.16, 26.15, 478.54, -1.304398008226, -0.103297414969, -1.144501530423, 4.0775],
AUTHORITY["EPSG", "6289"]],
PRIMEM["Greenwich", 0.000000,
AUTHORITY["EPSG","8901"]],
UNIT["degree (supplier to define representation)", 0.0174532925199433,
AUTHORITY["EPSG", "9122"]],
AXIS["Lat", NORTH],
AXIS["Long", EAST],
AUTHORITY["EPSG", "4289"]],
PROJECTION ["Oblique Stereographic"],
PARAMETER ["Latitude_Of_Origin", 52.1561605555555556],
PARAMETER ["Central_Meridian", 5.3876388888888889],
PARAMETER ["Scale_Factor", 0.9999079],
PARAMETER ["False_Easting", 155000.0],
PARAMETER ["False_Northing", 463000.0],
UNIT["metre", 1.0,
AUTHORITY["EPSG", "9001"]],
AXIS["X", EAST],
AXIS["Y", NORTH],
AUTHORITY["EPSG", "28992"]]
You see the TOWGS84 parameters are different.
Maybe you should discuss the issue at https://gis.stackexchange.com/ or ask Oracle support if they put wrong data in their reference.
Add-on
Check official EPSG data at http://www.epsg-registry.org/
When you search for
You get a bunch of transformations. I think you have to make some deeper investigations.