[QGIS-trac] Re: [Quantum GIS] #3645: synchronize QGIS' SRS definitions with GDAL's 1.8.0 SRS database

[Quantum GIS]

#3645: synchronize QGIS' SRS definitions with GDAL's 1.8.0 SRS database
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   Reporter:  nirvn                                      |              Owner:  nirvn        
       Type:  patch                                      |             Status:  assigned     
   Priority:  critical: causes crash or data corruption  |          Milestone:  Version 1.7.0
  Component:  Projection Support                         |            Version:  Trunk        
   Keywords:                                             |   Platform_version:               
   Platform:  All                                        |           Must_fix:  Yes          
Status_info:  0                                          |  
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Comment(by nirvn):

 jef, as mentioned over irc, the updated srs.db you applied in changeset
 15584 (http://trac.osgeo.org/qgis/changeset/15584) doesn't appear to have
 the latest definition for many datums (based in gdal 1.8).

 To give one example, the epsg 3148 (indian 1960 48n) in your srs.db is:
 +proj=utm +zone=48 +a=6377276.345 +b=6356075.41314024 +units=m +no_defs

 It's missing the +towgs84 declaration, found in latest gdal 1.8 and proj.4
 epsg file:
 +proj=utm +zone=48 +a=6377276.345 +b=6356075.41314024
 +towgs84=198,881,317,0,0,0,0 +units=m +no_defs

 Without the +towgs84 declaration, on the fly reprojection of wgs84 & epsg
 3148 datums have a +450m margin difference. It also affects coverting
 layers from one datum to the other using qgis' built-in "save as..."
 function.

 You based your updated srs.db on proj 4.7.0
 (http://trac.osgeo.org/proj/browser/tags/4.7.0/proj/nad/epsg) which the
 devs synched with latest gdal definitions afterwards
 (http://trac.osgeo.org/proj/browser/trunk/proj/nad/epsg).

 Would it be possible to ship 1.7 with a srs.db synched with gdal latest
 datum definitions?

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Ticket URL: <http://trac.osgeo.org/qgis/ticket/3645#comment:4>
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