[Qgis-developer] v.generalize in Processing: wrong output projection

Andre Joost andre+joost at nurfuerspam.de
Sun Oct 19 02:30:34 PDT 2014


Am 19.10.2014 09:31, schrieb Paolo Cavallini:
> Hi all. Applying v.generalize through Processing on data with prj:
>
> PROJCS["ED50_UTM_zone_30N",GEOGCS["GCS_European_1950",DATUM["D_European_1950",SPHEROID["International_1924",6378388,297]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-3],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["Meter",1]]
>
>
>
>generates an output with a wrong prj:
>
> PROJCS["UTM_Zone_30_Northern_Hemisphere",GEOGCS["GCS_international",DATUM["D_unknown",SPHEROID["International_1924",6378388,297]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-3],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["Meter",1]]
>
>
>
>that is interpreted by QGIS as a custom projection (USER:100007 -  *
> SR generato (+proj=utm +zone=30 +ellps=intl +units=m +no_defs)).
>

The parameters are the same, so not really wrong. QGIS often does not 
recognize similar projections when the name does not fit.

The only thing missing is the +wgs84 parameter from EPSG:23030:

+proj=utm +zone=30 +ellps=intl +towgs84=-87,-98,-121,0,0,0,0 +units=m 
+no_defs

Those parameters are often ignored in shapefiles, and QGIS does not find 
the right EPSG code without them.

Greetings,
André Joost



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