[Qgis-developer] addendum to SRS db
Paolo Cavallini
cavallini at faunalia.it
Mon Dec 28 02:33:26 EST 2009
Hi all.
Standard EPSG code for Italian projections (3003 and 3004) do not
include datum; as a result, reprojection is always wrong by about 100 m.
Can we add 4 more projection definition to our SRS database?
It should only be added the +towgs84 parameter so that we'll have:
3003 corrected, mainland: same as 3003, with
+towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
3004 corrected, mainland: same as 3004, with
+towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
3003 corrected, Sardinia: same as 3003, with
+towgs84=-168.6,-34.0,38.6,-0.374,-0.679,-1.379,-9.48
3004 corrected, Sicily: same as 3004, with
+towgs84=-50.2,-50.4,84.8,-0.690,-2.012,0.459,-28.08
In GRASS this has been solved by a similar approach:
http://freegis.org/cgi-bin/viewcvs.cgi/*checkout*/grass/src/libes/gis/datumtransform.table?rev=HEAD&content-type=text/plain
I think this can be done now, as it does not impact anything else, and
it would make life a lot easier for Italian users (remember, the second
largest QGIS user community!).
Details in http://www.crs-geo.eu/
Thanks a lot.
--
http://www.faunalia.it/pc
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