2

I have a shapefile with something similar to EPSG Projection 31256 - MGI / Austria GK East. However, the EPSG code states a false easting value of 0, while my prj file contains 750000 (that's probably also the reason why ArcGIS doesn't suggest any transformation parameters and thus won't reproject my shapefile?).

How can I define my false easting value when I want to re-project my shapefile from epsg:31256 to WGS 84 / UTM zone 33N (epsg:32633)?

Do I miss something?

3

Take first the proj4 parameters with gdalsrsinfo

gdalsrsinfo epsg:31256 -o proj4
'+proj=tmerc +lat_0=0 +lon_0=16.33333333333333 +k=1 +x_0=0 +y_0=-5000000 +ellps=
bessel +towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 +units=m +no_def
s '

Now re-use the proj4 string with ogr2ogr, but write your own false easting

ogr2ogr -f "ESRI Shapefile" -s_srs='+proj=tmerc +lat_0=0 +lon_0=16.33333333333333 +k=1 +x_0=750000 +y_0=-5000000 +ellps=bessel +towgs84=577.326,90.129,463.919,5.137,1.474,5.297,2.4232 +units=m +no_defs ' -t_srs epsg:32633 output.shp input.shp

The name of your desired output SRS seems to be "WGS 84 / UTM zone 33N", not just "WGS84" - please edit your question. Also don't call your input SRS as epsg:31256 because it is not, say rather that it is alike but with non-standard false easting.

  • Nice workaround, thank you! Curious how you do this in ArcGIS though... (also changed the additional info, thanks for pointing out) – GeoEki Mar 24 '17 at 8:54
  • In ArcGIS it might be enough to edit the .prj file spatialreference.org/ref/epsg/31256/prj and write that fake false easting into it. – user30184 Mar 24 '17 at 8:59

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