Feature request #2332
please add +towgs parameters
|Pull Request or Patch supplied:||No||Resolution:|
|Easy fix?:||No||Copied to github as #:||12392|
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
3004 corrected, mainland: same as 3004, with
3003 corrected, Sardinia: same as 3003, with
3004 corrected, Sicily: same as 3004, with
In GRASS this has been solved by a similar approach:
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/
New custom codes should be in the 32,768-100,000 range; 39031, 39032, 39041, 39042 should be ok.
#1 Updated by Giovanni Manghi over 10 years ago
Italy is not the only case, there are obviously others (in my case I'm referring to Portugal).
My suggestion is to implement this #1908 and then just maintain the list of datum association (3 and 7 parameters transformation).
Missing/correct definitions for Portugal
- [D73HG] HAYFORD-GAUSS DATUM 73
+proj=tmerc +lat_0=39.66666666666666 +lon_0=-8.131906111111112 +k=1 +x_0=180.598 +y_0=-86.98999999999999 +ellps=intl +towgs84=-239.749,88.181,30.488,0.263,0.082,1.211,2.229
- [DLXHG] HAYFORD-GAUSS DATUM LISBOA (IGP)
+proj=tmerc +lat_0=39.66666666666666 +lon_0=-8.131906111111112 +k=1 +x_0=0 +y_0=0 +ellps=intl +towgs84=-288.885,-91.744,126.244,-1.691,0.410,-0.211,-4.598
- [DLXHGMIL] HAYFORD-GAUSS DATUM LISBOA (Militar)
+proj=tmerc +lat_0=39.66666666666666 +lon_0=-8.131906111111112 +k=1 +x_0=200000 +y_0=300000 +ellps=intl +towgs84=-288.885,-91.744,126.244,-1.691,0.410,-0.211,-4.598