[GRASS-dev] Re: [GRASS GIS] #667: please allow to export projection information in more formats

[GRASS GIS]

#667: please allow to export projection information in more formats
--------------------------+-------------------------------------------------
  Reporter:  timmie       |       Owner:  grass-dev at lists.osgeo.org
      Type:  enhancement  |      Status:  new                      
  Priority:  normal       |   Milestone:  6.5.0                    
 Component:  default      |     Version:  svn-develbranch6         
Resolution:               |    Keywords:  g.proj                   
  Platform:  Linux        |         Cpu:  x86-32                   
--------------------------+-------------------------------------------------
Comment (by hamish):

 > Do you not think that the format +proj=longlat +ellps=WGS84 +datum=WGS84
 ...
 > cannot be converted back to the corresponding EPSG number?

 adding datum transform parameters is a non-reversible process.
 likely there is precision and other translation/expansion issues as well.
 Neither Frank's EPSG DB -> PROJ.4 epsg file nor QGIS's +proj4
 term matching code has a solution yet, and that's before you consider that
 we maintain our own ellipse and datum tables which
 may add and/or modify terms.

 I don't want to say it can't be done, but it's not easy and I would not
 trust well any result which claims to be able do it to be complete. IMHO
 better to just use the explicit expanded version and not worry..



 Hamish

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/667#comment:7>
GRASS GIS <http://grass.osgeo.org>