[Proj] truble to translate coordinates from WGS84 to EPSG:31287
Paul Kelly
paul-grass at stjohnspoint.co.uk
Thu Oct 28 07:35:55 EST 2010
On Thu, 28 Oct 2010, Markus Hetzmannseder wrote:
> On Thu, 28 Oct 2010, Jean-Claude Repetto wrote:
>
>> I get the same results as geoland.at :
>>
>> cs2cs +init=epsg:4326 +to +proj=lcc +lat_1=49 +lat_2=46 +lat_0=47.5
>> +lon_0=13.33333333333333 +x_0=400000 +y_0=400000 +ellps=bessel
>> +towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 +units=m +no_defs
>> 14.2833092 48.3098392
>> 470507.17 490503.01 -45.92
>> 16.371345 48.211996
>> 625724.58 483601.74 -44.45
>> 9.747076 47.503042
>> 130056.92 406637.21 -48.36
>
> Oh thx a lot, i did it that way, to get the wrong results:
> proj +proj=lcc +lat_1=49 +lat_2=46 +lat_0=47.5 +lon_0=13.33333333333333
> +x_0=400000 +y_0=400000 +ellps=bessel
> +towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 +units=m +no_defs
>
> And its looking like that josm-plogin is doing the same. Now i know at
> least how to generate the real projektion with the proj-toolbox itself.
> Now the plugin should be able to be changed in a similar way to use the
> cs2cs arguments.
The proj command does a simple forward projection and ignores the +towgs84
datum transformation parameters. The cs2cs command takes these into
account to give a more accurate result. If you leave off the +towgs84
parameters from the cs2cs command line you will get the same result as
with the proj command line. It looks to me like the JOSM plugin is not
doing the datum transformation, only the projection (I had a quick glance at
<http://svn.openstreetmap.org/applications/editors/josm/plugins/epsg31287/src/com/jhlabs/map/proj/LambertConformalConicProjection.java>)
to confirm this) - but that is certainly not easy to fix.
Best regards
Paul Kelly
More information about the Proj
mailing list