[Proj] Proj 4.9.1RC3 Released

[Sebastiaan Couwenberg]

On 02/21/2015 08:22 PM, Hermann Peifer wrote:
> On 2015-02-21 18:31, Howard Butler wrote:
>> All,
>>
>> Proj4 4.9.1RC3 is now released for testing. Should no significant issues be identified, ...
> (...)
>>>
>>>   o Regenerate nad/epsg with GDAL r28536 to avoid precision loss in TOWGS84
>>>     parameters, e.g. on Amersfoort / RD EPSG:4289 (#260)
> 
> No sure if this is significant, but instead of a precision loss for 
> TOWGS84's X,Y,Z-offsets, there is now a "precision gain" for the 
> rotation values in several cases, e.g. for the mentioned Amersfoort / RD 
> EPSG:4289. I wonder if this is as it should be.

The Dutch Kadaster raised the issue about the imprecise +towsg84 values
for EPSG:28992 on the dutch OSGeo list. See the link included in #260.

https://trac.osgeo.org/proj/ticket/260
http://lists.osgeo.org/pipermail/dutch/2014-October/000980.html

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.

Kind Regards,

Bas

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