[QGIS-trac] Re: [Quantum GIS] #377: custom projection of GRASS vectors

[Quantum GIS]

#377: custom projection of GRASS vectors
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        Reporter:  lami at faunalia.it                  |         Owner:  homann       
            Type:  defect                            |        Status:  closed       
        Priority:  major: does not work as expected  |     Milestone:  Version 1.0.3
       Component:  GRASS                             |       Version:  0.8          
      Resolution:  fixed                             |      Keywords:               
Platform_version:                                    |      Platform:  Unix         
        Must_fix:  No                                |   Status_info:  1            
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Changes (by rblazek):

  * status:  assigned => closed
  * resolution:  => fixed

Comment:

 Seems to work correctly in revision #10899 (QGIS 1.2 unstable), PROJ.4
 4.6.0, GRASS 7.0 (revision #36903).
 I have tested with 2 GRASS locations:

 name: Transverse Mercator
 datum: rome40
 datumparams: towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
 proj: tmerc
 ellps: international
 a: 6378388.0000000000
 es: 0.0067226700
 f: 297.0000000000
 lat_0: 0.0000000000
 lon_0: 9.0
 k_0: 0.9996000000
 x_0: 1500000.0000000000

 and

 name: Lat/Lon
 proj: ll
 datum: wgs84
 ellps: wgs84
 no_defs: defined

 and vector reprojected with v.proj. There is no shift if the vectors from
 those 2 locations are displayed in QGIS. To be sure that the datum shift
 is realy used and I am on the right zoom level I tried to remove
 'datumparams' from the first location and a shift appeared.

 Important is, that QgsCoordinateReferenceSystem::findMatchingProj
 correctly does not find srsid now which was the case of previous versions
 according to comments in [https://trac.osgeo.org/qgis/ticket/418] and thus
 correct pure PROJ.4 string including +towgs is used. So it seems that
 OSRIsSame in PROJ.4 was fixed to use also towgs params.

 Radim

-- 
Ticket URL: <https://trac.osgeo.org/qgis/ticket/377#comment:16>
Quantum GIS <http://qgis.org>
Quantum GIS is an Open Source GIS viewer/editor supporting OGR, PostGIS, and GRASS formats