[QGIS-trac] [Quantum GIS] #3787: Problem Datum Transformation

[Quantum GIS]

#3787: Problem Datum Transformation
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   Reporter:  ImPreZa                                                           |              Owner:  nobody       
       Type:  bug                                                               |             Status:  new          
   Priority:  major: does not work as expected                                  |          Milestone:  Version 1.7.0
  Component:  Projection Support                                                |            Version:  1.6.0        
   Keywords:  datum transformation SAD69 SIRGAS2000 problem displacement shift  |   Platform_version:  Win7         
   Platform:  Windows                                                           |           Must_fix:  Yes          
Status_info:  0                                                                 |  
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 Hey!!

 I've tried to transform a shapefile from EPGS:4618 (SAD69) to EPGS:4674
 (SIRGAS2000), but the product of this transformation doesn't shifts. It
 seems that QGIS export a shapefile with the new projection, but it is
 unable to apply (in fact) the values of the new ellipsoid.

 Here are the official parameters for transformation between the both
 datums:[[BR]]
 DX = -67,35[[BR]]
 DY = +3,88[[BR]]
 DZ = -38,22[[BR]]


 I've attached the .gsb files (NTV2 transformation) used by the department
 of the brazilian government, IBGE, which is responsible for cartography
 etc.

 SAD69 Original (SAD69_003.GSB) [[BR]]
 SAD69 reviewed in 1996 (SAD96_003.GSB)

 If I open in QGIS a shapefile originally created in ArcGIS in SAD69 and
 other in SIRGAS2000, also transformed from SAD69 to SIRGAS in ArcGIS,
 without activate OTF, I can see the displacement between them. But when I
 transform the ArcGIS-shapefile-SAD69 to SIRGAS2000 in QGIS, the QGIS is
 unable to show their displacement, even with OTF activated. Why does this
 happens with shapes transformed in QGIS?

 And the last problem: The QGIS doesn't create properly the .prj file, both
 for SAD69 and SIRGAS2000, as exposed here:

 '''SIRGAS2000'''[[BR]]

 GEOGCS["GRS 1980(IUGG,
 1980)",DATUM'''["D_unknown"''',SPHEROID["GRS80",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]

 And the correct one, from ArcGIS is:

 GEOGCS["GCS_SIRGAS_2000",DATUM["D_SIRGAS_2000",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]

 '''SAD69:'''[[BR]]

 GEOGCS["Australian Natl & S. Amer.
 1969",DATUM["D_unknown",SPHEROID["aust_SA",6378160,298.25]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]

 And the correct one, from ArcGIS is:

 GEOGCS["GCS_South_American_1969",DATUM["D_South_American_1969",SPHEROID["GRS_1967_Truncated",6378160.0,298.25]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],VERTCS["WGS_1984_Geoid",VDATUM["WGS_1984_Geoid"],PARAMETER["Vertical_Shift",0.0],PARAMETER["Direction",1.0],UNIT["Meter",1.0]]

 Here are the original data that I'm working with. These data are mineral
 rights from Rio Grande do Sul State, south Brazil:
 [http://sigmine.dnpm.gov.br/sad69/RS.zip/ Shapefiles in SAD69]
 [http://sigmine.dnpm.gov.br/sirgas2000/RS.zip/ Shapefiles in SIRGAS]

 I asked for help at the QGIS Forum. They've found the same problem and
 couldn't solve it.
 Thanks!!

-- 
Ticket URL: <https://trac.osgeo.org/qgis/ticket/3787>
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