SVY21 (EPSG 3414)

[Anonymous]

Hi, I am using AutoCAD Map 3D to tranform current coordinate system to SVY21. I cannot find SVY21 in the library. Does anyone know how to do it?

Thanks a lot.

Siping

[gluckett]

Under Map Setup, use the Create Coordinate System to create a new one from scratch.

[Anonymous]

Thanks, gluckett.

After I tranformed the coordiantes in WGS84 to SVY21 using the way you taught me, I found the transformation is not perfect. For example:

WGS84: 

Lat = 1.2803, Lon = 103.8504

SVY21:
x = 29900.2891, y = 29190.1725

However, the converter in http://dominoc925.blogspot.sg/p/svy21-coordinate-converter.html 's gets

x = 29901.023548426907, y = 29194.595522157477

Is there anything I missed here? Could you share your WKT for me to check? Thanks.

My WKT:

PROJCS["SVY21 / Singapore TM",

GEOGCS["LL84",

DATUM["WGS84",

SPHEROID["WGS84",6378137.000,298.25722293],

TOWGS84[0.0000,0.0000,0.0000,0.000000,0.000000,0.000000,0.00000000]],

PRIMEM["Greenwich",0],

UNIT["Degree",0.017453292519943295]],

PROJECTION["Transverse_Mercator"],

PARAMETER["false_easting",28001.642],

PARAMETER["false_northing",38744.572],

PARAMETER["scale_factor",1.000000000000],

PARAMETER["central_meridian",103.83333333333300],

PARAMETER["latitude_of_origin",1.36666666666667],

UNIT["Meter",1.00000000000000]

]

[gluckett]

Try the settings from Spatial Reference:

http://www.spatialreference.org/ref/epsg/svy21-singapore-tm/prettywkt/

[Anonymous]

I have already compared this reference with my setting. The only difference could be in SPHEROID

SPHEROID["WGS 84",6378137,298.257223563,
                AUTHORITY["EPSG","7030"]]

while in my WKT:

SPHEROID["WGS84",6378137.000,298.25722293] 

I could not find the SPHEROID "WGS84" with the same parameter in AutoCAD's library.

Thanks.

Siping