[gdal-dev] could GDAL enforce towgs84=0,0,0 for ETRS89-based CRSs?

[Maciej Sieczka]

Hi,

Due to a change in PROJ 4.6.0, no datum shift is aplied when
reprojecting between a CRS which has an implicit datum definition (e.g.
Pulkovo 1942/58-based EPSG 4179, for which GDAL uses
towgs84=33.4,-146.6,-76.3,-0.359,-0.053,0.844,-0.84) and an ETRS89-based
CRS, e.g. EPSG 2180, that has no implicit towgs84 or datum.

The above results in reprojection errors of about 150 m and makes using
EPSG codes for ETRS89-based CRS impossible. Could PROJ.4 and GDAL
enforce towgs84=0,0,0 for all ETRS89 CRSs that have no implicit datum
definition otherwise?

For instance, GRASS always forces towgs84=0,0,0 for EPSG 2180 and does
the reprojection right.

Maciek

-- 
Maciej Sieczka
www.sieczka.org