[Proj] Proj 4.9.1RC3 Released

[Hermann Peifer]

On 2015-02-21 20:43, Sebastiaan Couwenberg wrote:
>
> The correct values specified by Kadaster use 6 decimals max:
>
> +towgs84=565.4171,50.3319,465.5524,-0.398957,0.343988,-1.877402,4.0725
>
> This used to be:
>
> +towgs84=565.417,50.3319,465.552,-0.398957,0.343988,-1.8774,4.0725
>
> And is now:
>
> +towgs84=565.4171,50.3319,465.5524,-0.398957388243134,0.343987817378283,-1.87740163998045,4.0725
>
> The "precision gain" is better than what we had before, but it may also
> make sense to limit the number of decimals in GDAL a bit.
>

As far as I can see: the EPSG database has Coordinate Frame Rotation 
values in microradian, see: 
http://epsg-registry.org/export.htm?wkt=urn:ogc:def:coordinateOperation:EPSG::4830

If one reverts the sign, converts to arc seconds and prints the result 
with "%.15g" format, one ends up with what the values are now, e.g.
rX = 1.9342 microradian => -0.398957388243134 arc seconds

The result does indeed look a bit like having some overprecision.

Hermann