[Proj] +towgs84 approximation error

[Antoine Cottin]

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
Antoine
-----------------------
Dr Antoine Cottin
Chief Technology Officer
Carbomap Ltd.
Edinburgh Centre for Carbon Innovation
High School Yards
Edinburgh EH1 1LZ
-----------------------
http://www.carbomap.com
http://carbomap.wordpress.com
http://github.com/carbomap
@carbomap
+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.
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