[gdal-dev] Wrong .prj file with SHAPEZIP Outputformat

Guillaume Sueur no-reply at neogeo-online.net
Thu May 16 02:48:57 PDT 2013


Hi list(s),

Sorry for cross-posting gdal and mapserver dev lists, but I don't know 
exactly where my problem comes from.

When using a SHAPEZIP OUTPUTFORMAT with MapServer, I retrieve a prj file 
which is not exactly the correct projection definition (for EPSG:3946) :

PROJCS["Lambert_Conformal_Conic",GEOGCS["GCS_GRS 1980(IUGG, 
1980)",DATUM["D_unknown",SPHEROID["GRS80",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["standard_parallel_1",45.25],PARAMETER["standard_parallel_2",46.75],PARAMETER["latitude_of_origin",46],PARAMETER["central_meridian",3],PARAMETER["false_easting",1700000],PARAMETER["false_northing",5200000],UNIT["Meter",1]]

I took a look at the code in mapogroutput.c and noticed it was all 
driven by OGR.

So I did the same extract to a EPSG:3946 shapefile with ogr2ogr. It 
gives the correct result :

PROJCS["RGF93_Lambert_93",GEOGCS["GCS_RGF93",DATUM["D_RGF_1993",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["standard_parallel_1",49],PARAMETER["standard_parallel_2",44],PARAMETER["latitude_of_origin",46.5],PARAMETER["central_meridian",3],PARAMETER["false_easting",700000],PARAMETER["false_northing",6600000],UNIT["Meter",1]]

which makes the shapefile's projection understandable by QGIS.

So, the question is : where does the prj definition generated by 
mapserver come from ? Why is it wrong and how to fix this ?

Best regards

Guillaume


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