[Proj] +towgs84 approximation error

Antoine Cottin a.cottin at carbomap.com
Thu Mar 23 04:47:10 EST 2017

Hello Jochem,

As one mentioned, and i know it’s not answering your question.
But what kind of data (and sensor) did you have/used to reach this accuracy?
And how do you calculate this accuracy, what reference data did you used?

Thanks for enlightening me.
Best regards
Dr Antoine Cottin
Chief Technology Officer
Carbomap Ltd.
Edinburgh Centre for Carbon Innovation
High School Yards
Edinburgh EH1 1LZ
+44 (0)7577 444-046

> On 23 Mar 2017, at 09:21, Jochem <jochem.lesparre at kadaster.nl> wrote:
> Hi Kristian,
> I can not show that cs2cs makes an approximation error by using only cs2cs.
> I have to compare it with other software. But what transformation software
> is available to you that would you trust more than Proj.4? The best way to
> show it, is to compute a transformation in computational software like
> Matlab twice. One time with the approximate formulas, giving the same result
> as cs2cs, and one time with the strict formulas, giving a 4 cm different
> result. As not everyone here will have Matlab, I am thinking of using Excel.
> Do you think that is a good idea?
> Thanks for the information on how to use a development version of PROJ.4
> with QGIS. This sounds complicated. Maybe I would manage to do it with a lot
> of effort and some help. But I am afraid I can't expect the government
> agency here to reproduce that.
> In the Netherlands, the official transformation RDNAPTRANS will probably be
> updated this year in a way that it can be done with Proj.4. I hoped to be
> able to do the same here, but the approximation error is preventing me from
> doing so.
> Regards, Jochem
> --
> View this message in context: http://osgeo-org.1560.x6.nabble.com/towgs84-approximation-error-tp5313738p5313821.html
> Sent from the PROJ.4 mailing list archive at Nabble.com.
> _______________________________________________
> Proj mailing list
> Proj at lists.maptools.org
> http://lists.maptools.org/mailman/listinfo/proj

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.maptools.org/pipermail/proj/attachments/20170323/c2b67b40/attachment.htm 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 842 bytes
Desc: Message signed with OpenPGP using GPGMail
Url : http://lists.maptools.org/pipermail/proj/attachments/20170323/c2b67b40/attachment.pgp 

More information about the Proj mailing list