[Proj] cs2cs: Gauss-Krüger to WGS84
traut at gmx.de
Mon Dec 10 06:09:46 EST 2012
On 12-12-10 0:41, Jose Gonçalves wrote:
> cs2cs +init=/usr/local/share/proj/world:gk4-d +towgs84
> the result is
> 56d30'44.77"E 39d38'19.023"N 0.000
> This use of cs2cs is not correct. You must run something like:
> cs2cs /string_for_system_1/ +to/string_for_system2/
That's not what I did? I thought that
would be system1 and that
would include the system2 part.
> The +towgs84=... is the part of a string that you use to give datum
> parameters of that system
> That's far away. Another online example names:
> cs2cs +init=epsg:31466 +to +init=epsg:4326
> which returns even worse:
> 32d6'20.91"E 46d39'54.638"N 16.676
> The EPSG code 31466 is for GK zone 2. Your X coordinate is very large,
> so it is more likely that the point is in a different zone, probably 4,
> which has a false easting of 4500 km. In that case you get:
I had missed 314666 vs. 31468, although I used gk4 above.
> echo 4491957.175 5511210.407 | cs2cs +init=epsg:31468 +to +init=epsg:4326
> 11d53'13.028"E 49d44'14.871"N 48.659
That's close enough to
11.88695229 49.73746425 (here)
11.88695 49.737475 (from a known opposite conversion)
But what's the third part of the output line? I did not mind as long as
it was 0.000, but I do not see it documented.
> At least this point is in Germany... The datum transformation parameters
> used are the following:
That's done automagically? Or do I have to apply this anywhere?
I'm just lost in the docu, where to find the epsg ids, how to apply
towgs84 and and how to read the output.
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