I have a shapefile that also contains a proj file that looks like so:
PROJCS [ "MGI_Austria_Lambert", GEOGCS [ "GCS_MGI", DATUM [ "D_MGI", SPHEROID["Bessel_1841",6377397.155,299.1528128] ], PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433] ], PROJECTION["Lambert_Conformal_Conic"], PARAMETER["False_Easting",400000.0], PARAMETER["False_Northing",400000.0], PARAMETER["Central_Meridian",13.33333333333333], PARAMETER["Standard_Parallel_1",46.0], PARAMETER["Standard_Parallel_2",49.0], PARAMETER["Latitude_Of_Origin",47.5], UNIT["Meter",1.0] ]
I want to convert this shapefile into a geojson like so:
ogr2ogr -f GeoJSON \ -s_srs STATISTIK_AUSTRIA_STADTREGIONEN_3MIO.prj \ -t_srs EPSG:4326 \ STATISTIK_AUSTRIA_STADTREGIONEN_3MIO.geojson \ STATISTIK_AUSTRIA_STADTREGIONEN_3MIO.shp
This fails with the following error message:
ERROR 6: No translation for Lambert_Conformal_Conic to PROJ.4 format is known.
Changing the proj file to contain either
PROJECTION["Lambert_Conformal_Conic_1SP"] instead of
Lambert_Conformal_Conic results in valid geojson files that seem to have the correct coordinates BUT the resulting coordinates differ in their 2nd or 3rd decimal places, e.g.,
LON , LAT 16.526053978650904, 48.32876392574797
My questions are:
- Which one of the two (if any) is the correct result?
- Is there a intuitive explanation for the difference between Lambert_Conformal_Conic, ~_1SP, and ~_2SP that also a non-cartographer is able to understand.
- There is an inaccuracy in the value of the
GEOGCS UNITvalue in the proj displayed above compared to the value given for the respective projection at spatialreference.org. Is this the reason for the differences?
- The publisher of the dataset states that there is a more accurate (but non-free) version (
1:3000000) of the data. May it be that the inaccuracies due to the data source is bigger than the inaccuracies due to inaccurate re-projection?