ogr2ogr -s_srs "+init=epsg:26592" -t_srs "+init=epsg:32633"

[robertoangeletti@…]

Hello Frank,

I am transforming SHP from Italian GaussBoagaEst to Wgs84 33 and have founded a shift of 164.57 meters on Y.

I tested with command:

ogr2ogr -s_srs "+init=epsg:26592" -t_srs "+proj=utm +zone=33 \
   +datum=WGS84" c:/gis/exportedSHP %1

and also with:

ogr2ogr -s_srs "+init=epsg:26592" -t_srs "+init=epsg:32633" \
   c:/gis/exportedSHP %1

Possibly, I wronged EPSG ID? The 26592 is not Italian GaussBoagaEst? Or, there is an error in ogr2ogr? I am using FWTools1.0.7

Thank you in advance for help.

Best Regards

Roberto Angeletti

[joehealy]

I believe that epsg:26592 does not specify a towgs84 parameter so no datum shift will be taking place.

To make this work, you will need to obtain some appropriate datum shift parameters to transform from the international ellipsoid to the wgs84 ellipsoid.

This ​http://osdir.com/ml/gis.proj-4.devel/2004-06/msg00017.html will hopefully help.

The definition I have for epsg:26592

+proj=tmerc +lat_0=0 +lon_0=2.54766666666666 +k=0.9996 +x_0=2520000 +y_0=0 +ellps=intl +pm=rome +units=m +no_defs

which is lacking either a datum parameter or a towgs84 parameter.

A command line that should work would be:

ogr2ogr -s_srs "+proj=tmerc +lat_0=0 +lon_0=2.54766666666666 +k=0.9996 +x_0=2520000 +y_0=0 +ellps=intl +pm=rome +units=m +towgs84=v1,v2,v3,v4,v5,v6,v7" -t_srs "+proj=utm +zone=33 \

+datum=WGS84" c:/gis/exportedSHP %1

where v1 through v7 are the datum shift values you need.