[QGIS-trac] [Quantum GIS] #3586: use authid instead of proj.4 strings

[Quantum GIS]

#3586: use authid instead of proj.4 strings
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   Reporter:  jef                               |              Owner:  jef          
       Type:  patch                             |             Status:  new          
   Priority:  major: does not work as expected  |          Milestone:  Version 1.7.0
  Component:  Projection Support                |            Version:               
   Keywords:                                    |   Platform_version:               
   Platform:  All                               |           Must_fix:  No           
Status_info:  0                                 |  
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 Currently we try to use the proj.4 strings to store references to
 coordinate
 systems (eg. for the default project crs).  Unfortunately the proj.4
 string isn't unique in our database:

 {{{
 sqlite> select count(*),parameters from tbl_srs group by parameters order
 by count(*) desc limit 10;
 54|+proj=longlat +ellps=intl +no_defs
 27|+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs
 21|+proj=longlat +ellps=clrk80 +no_defs
 17|+proj=longlat +ellps=bessel +no_defs
 15|+proj=longlat +ellps=clrk66 +no_defs
 13|+proj=longlat +a=6378249.2 +b=6356515 +no_defs
 11|+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs
 9|+proj=longlat +ellps=GRS80 +no_defs
 9|+proj=longlat +ellps=krass +no_defs
 9|+proj=tmerc +lat_0=0 +lon_0=105 +k=1 +x_0=500000 +y_0=0 +ellps=krass
 +units=m +no_defs
 sqlite> select auth_name,auth_id,description,parameters from tbl_srs where
 parameters='+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs'
 limit 1;
 EPSG|4148|Hartebeesthoek94|+proj=longlat +ellps=WGS84
 +towgs84=0,0,0,0,0,0,0 +no_defs
 }}}

 So selecting 'EPSG:4326' as default CRS results in 'EPSG:4148 -
 Hartebeesthoek94' - which obviously is irritating.

 The attached patch switches to the use of authid instead of proj.4
 strings.  Any objections to commit it for 1.7?

-- 
Ticket URL: <http://trac.osgeo.org/qgis/ticket/3586>
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