Bug report #3788

Problem Datum Transformation

Added by ImPreZa - about 13 years ago. Updated over 11 years ago.

Category:Projection Support
Affected QGIS version:master Regression?:No
Operating System:Windows Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:13846



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:

DX = -67,35
DY = +3,88
DZ = -38,22

Unfortunately, I couldn't upload the .gsb files (NTV2 transformation, 800kb) used by the department of the brazilian government, IBGE, which is responsible for cartography etc. But you can download it here ([ftp://geoftp.ibge.gov.br/programa/Transformacao_de_Coordenadas/ ProGRID IBGE]). You'll find the .gsb files here (C:\\Program Files\\Progrid\\GridFiles).

SAD69 Original (SAD69_003.GSB)
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:


GEOGCS[[GRS 1980(IUGG 1980)"DATUM*["D_unknown"*SPHEROID["GRS80"6378137298257222101]]PRIMEM["Greenwich"0]UNIT["Degree]]

And the correct one, from ArcGIS is:



GEOGCS[[Australian Natl & S Amer 1969"DATUM["D_unknown"SPHEROID["aust_SA"637816029825]]PRIMEM["Greenwich"0]UNIT["Degree]]

And the correct one, from ArcGIS is:


Here are the original data that I'm working with. These data are mineral rights from Rio Grande do Sul State, south Brazil:
Shapefiles in SAD69
Shapefiles in SIRGAS

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


#1 Updated by Giovanni Manghi over 12 years ago

  • Target version changed from Version 1.7.0 to Version 1.7.4

#2 Updated by Paolo Cavallini about 12 years ago

  • Crashes QGIS or corrupts data set to No
  • Affected QGIS version set to master
  • Target version changed from Version 1.7.4 to Version 1.8.0

#3 Updated by Paolo Cavallini over 11 years ago

  • Target version changed from Version 1.8.0 to Version 2.0.0

#4 Updated by Magnus Homann over 11 years ago

  • Pull Request or Patch supplied set to No
  • Assignee deleted (nobody -)
  • Status changed from Open to Closed

It seems to work now, I have gdal 1.9.1. I can see a difference when setting different projections for the layers. Save as yields:

GEOGCS["SIRGAS 2000",DATUM["D_SIRGAS_2000",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]]



in respective project file.

Closing, please reopen if it persists.

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