[GRASS-dev] [GRASS GIS] #2282: r.external.out: keep GRASS maps and external files in sync

[GRASS GIS]

#2282: r.external.out: keep GRASS maps and external files in sync
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 Reporter:  sbl          |       Owner:  grass-dev@…              
     Type:  enhancement  |      Status:  new                      
 Priority:  normal       |   Milestone:  7.1.0                    
Component:  Default      |     Version:  unspecified              
 Keywords:               |    Platform:  Unspecified              
      Cpu:  Unspecified  |  
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Comment(by glynn):

 Replying to [ticket:2282 sbl]:

 > At the moment, GRASS maps and external files produced using
 r.external.out are not fully kept in sync.
 >
 > This applies both when maps are renamed or removed. Names of external
 files are not changed by g.rename and files are not deleted by g.remove or
 g.mremove.

 This behaviour is intentional; well, maybe "not entirely unintentional" is
 more accurate.

 If that's to change, it would need to be e.g. an option set by
 r.external.out (for the default) and r.external (to allow it to be changed
 for individual maps).

 Certainly, it needs to be possible to delete the "link" which allows GRASS
 to treat the file as a raster map without deleting the file itself. And
 given that the existing g.remove behaviour is to remove the link but leave
 the actual data, I'm not sure that should change (i.e. removing both the
 link and the file needs a new flag, so no-one loses data unexpectedly).

 Essentially, GDAL-linked maps are somewhat like a symlink to a file. Using
 "rm" on a symlink deletes the symlink, not the file it refers to.
 Similarly for "mv".

 The GRASS tools (g.remove, g.rename, g.copy etc) need to be able to
 manipulate the links. They don't necessarily have to be able to manipulate
 the files; the OS' own file-management tools can handle that. Although, in
 the case of renaming and copying, we should provide a convenient way to
 update/copy the links; running r.external requires providing all of the
 parameters again.

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/2282#comment:1>
GRASS GIS <http://grass.osgeo.org>