<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Apr 13, 2015 at 11:39 AM, Hermann Peifer <span dir="ltr"><<a href="mailto:peifer@gmx.eu" target="_blank">peifer@gmx.eu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>
About +towgs84=-129.19,-41.21,130.73,-.25,-.37,-.33,-2.96<br>
<br>
The EPSG database has pretty similar values for coordinate operations<br>
1458 and 1665, see e.g. at<br>
<a href="http://epsg-registry.org/export.htm?wkt=urn:ogc:def:coordinateOperation:EPSG::1665" target="_blank">http://epsg-registry.org/export.htm?wkt=urn:ogc:def:coordinateOperation:EPSG::1665</a><br>
<br>
These values are however given according to METHOD: Coordinate Frame<br>
Rotation. You'd need to revert the sign of the rotation values, as<br>
explained in<br>
<a href="https://trac.osgeo.org/proj/wiki/GenParms#towgs84-DatumtransformationtoWGS84" target="_blank">https://trac.osgeo.org/proj/wiki/GenParms#towgs84-DatumtransformationtoWGS84</a>,<br>
so you should use<br>
<br>
+towgs84=-129.19,-41.21,130.73,.25,.37,.33,-2.96<br></blockquote><div><br></div><div>If you reverse the sign then shouldn't it be:</div><div><br></div><div>+towgs84=129.19,41.21,-130.73,-.25,-.37,-.33,2.96<br></div><div> </div><div>or am I missing what you are suggesting?</div><div><br></div><div>Rich</div><div><br></div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">I am however not so sure if this will help you to get rid of a 200m offset.<br>
<br>
Hermann<br>
<span class=""><br>
On 2015-04-13 17:31, <a href="mailto:Michel.Dastous@bentley.com">Michel.Dastous@bentley.com</a> wrote:<br>
> Hi,<br>
><br>
> I’m currently trying to publish an Oracle dataset marked as SRID 82474<br>
> and cannot determine the proper proj4 init string corresponding to it.<br>
> I was able to extract the WKT definition from Oracle:<br>
><br>
</span>> /PROJCS["ACT Standard Grid (AGD66)", GEOGCS [ "Australian Geodetic 1966<br>
<span class="">> ACT", DATUM ["AGD 66 ACT", SPHEROID ["Australian", 6378160,<br>
> 298.25],-129.19,-41.21,130.73,-.25,-.37,-.33,-2.96], PRIMEM [<br>
> "Greenwich", 0.000000 ], UNIT ["Decimal Degree", 0.01745329251994330]],<br>
> PROJECTION ["Transverse Mercator"], PARAMETER ["Scale_Factor",<br>
> 1.000086], PARAMETER ["Central_Meridian", 149.0092948333], PARAMETER<br>
> ["False_Easting", 200000.000000], PARAMETER ["False_Northing",<br>
</span>> 4510193.4939], UNIT ["Meter", 1.000000000000]]/<br>
<span class="">><br>
> The best we have is:<br>
><br>
</span>> /+proj=tmerc +lon_0=149.0092948333 +k=1.000086 +x_0=200000<br>
> +y_0=4510193.4939 +ellps=aust_SA<br>
> +towgs84=-129.19,-41.21,130.73,-.25,-.37,-.33,-2.96 +units=m +no_defs <>/<br>
<span class="">><br>
> Unfortunately this produce a displacement of around 200 meters when<br>
> reprojected to Bing coordinate system.<br>
><br>
> Can anyone help?<br>
><br>
> Thanks,<br>
><br>
> Michel<br>
><br>
><br>
><br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr">Richard W. Greenwood, PLS<br><a href="http://www.greenwoodmap.com" target="_blank">www.greenwoodmap.com</a></div></div>
</div></div>