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

[PostGIS]

#1742: PostGIS 2.0 alters Z-coordinate
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 Reporter:  pramsey   |       Owner:  pramsey      
     Type:  defect    |      Status:  new          
 Priority:  critical  |   Milestone:  PostGIS 2.0.0
Component:  postgis   |     Version:  2.0.x        
 Keywords:            |  
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Comment(by pramsey):

 Mystery solved, it is nothing more mysterious than that PostGIS 2.0 uses
 this as the definition of EPSG:23030:
 {{{
 +proj=utm +zone=30 +ellps=intl +towgs84=-87,-98,-121,0,0,0,0 +units=m
 +no_defs
 }}}
 and PostIGIS 1.5 uses this
 {{{
 +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
 }}}
 Hey presto, there's an ellipsoid shift in there, so the X and Y
 coordinates also differ between versions. The killer though is that yes,
 Proj4.8 is now doing a Z-shift too, so the question becomes, what should
 we do with Z?

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1742#comment:2>
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