[postgis-devel] [PostGIS] #1742: PostGIS 2.0 alters Z-coordinate

[PostGIS]

#1742: PostGIS 2.0 alters Z-coordinate
-----------------------+----------------------------------------------------
  Reporter:  pramsey   |       Owner:  pramsey      
      Type:  defect    |      Status:  closed       
  Priority:  critical  |   Milestone:  PostGIS 2.0.0
 Component:  postgis   |     Version:  2.0.x        
Resolution:  invalid   |    Keywords:               
-----------------------+----------------------------------------------------

Comment(by lrssvt):

 +towgs84 parameter depends on the area where you are, within the UTM zone
 30.
 So it is at the discretion of the user who uses! For example, for Italy
 with EPSG:3004 or 3003, it is:

 {{{
 +towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68     Italy (Peninsular
 Part), Accuracy 3-4m
 +towgs84=-168.6,-34.0,38.6,-0.374,-0.679,-1.379,-9.48    Italy (Sardinia),
 Accuracy 3-4m
 +towgs84=-50.2,-50.4,84.8,-0.690,-2.012,0.459,-28.08     Italy (Sicily),
 Accuracy 3-4m
 }}}

 PostGIS 2.0 uses this:

 {{{
 +towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
 }}}

 so, for Sardinia that leads to gross errors!

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1742#comment:8>
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