[Proj] ACT Standard Grid (AGD66)

[Hermann Peifer]

About +towgs84=-129.19,-41.21,130.73,-.25,-.37,-.33,-2.96

The EPSG database has pretty similar values for coordinate operations 
1458 and 1665, see e.g. at 
http://epsg-registry.org/export.htm?wkt=urn:ogc:def:coordinateOperation:EPSG::1665

These values are however given according to METHOD: Coordinate Frame 
Rotation. You'd need to revert the sign of the rotation values, as 
explained in 
https://trac.osgeo.org/proj/wiki/GenParms#towgs84-DatumtransformationtoWGS84, 
so you should use

+towgs84=-129.19,-41.21,130.73,.25,.37,.33,-2.96

I am however not so sure if this will help you to get rid of a 200m offset.

Hermann

On 2015-04-13 17:31, Michel.Dastous at bentley.com wrote:
> Hi,
>
> I’m currently trying to publish an Oracle dataset marked as SRID 82474
> and cannot determine the proper proj4 init string corresponding to it.
> I was able to extract the WKT definition from Oracle:
>
> /PROJCS["ACT Standard Grid (AGD66)", GEOGCS [ "Australian Geodetic 1966
> ACT", DATUM ["AGD 66 ACT", SPHEROID ["Australian", 6378160,
> 298.25],-129.19,-41.21,130.73,-.25,-.37,-.33,-2.96], PRIMEM [
> "Greenwich", 0.000000 ], UNIT ["Decimal Degree", 0.01745329251994330]],
> PROJECTION ["Transverse Mercator"], PARAMETER ["Scale_Factor",
> 1.000086], PARAMETER ["Central_Meridian", 149.0092948333], PARAMETER
> ["False_Easting", 200000.000000], PARAMETER ["False_Northing",
> 4510193.4939], UNIT ["Meter", 1.000000000000]]/
>
> The best we have is:
>
> /+proj=tmerc +lon_0=149.0092948333 +k=1.000086 +x_0=200000
> +y_0=4510193.4939 +ellps=aust_SA
> +towgs84=-129.19,-41.21,130.73,-.25,-.37,-.33,-2.96 +units=m +no_defs  <>/
>
> Unfortunately this produce a displacement of around 200 meters when
>   reprojected to Bing coordinate system.
>
> Can anyone help?
>
> Thanks,
>
> Michel
>
>
>
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