[GRASS-dev] [GRASS GIS] #2428: r.external to accept gdal config options

[GRASS GIS]

#2428: r.external to accept gdal config options
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 Reporter:  perrygeo     |       Owner:  grass-dev@…              
     Type:  enhancement  |      Status:  new                      
 Priority:  normal       |   Milestone:  7.1.0                    
Component:  Default      |     Version:  svn-trunk                
 Keywords:  r.external   |    Platform:  Unspecified              
      Cpu:  x86-64       |  
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Comment(by neteler):

 Replying to [comment:2 glynn]:
 > Replying to [comment:1 neteler]:
 > > The request sounds reasonable but I didn't figure out how to pass
 "papszOptions" to GDAL as used in r.external. The magic line in r.out.gdal
 is this:
 >
 > > but in r.external GDALOpen() is used. Perhaps a GDAL expert can tell
 us the trick.
 >
 > Note that r.external is the analogue of r.in.gdal, which doesn't accept
 any configuration options.

 While it doesn't directly, I had added a larger cache some time ago by
 setting GDALSetCacheMax() to 300MB rather than the tiny 40MB default GDAL
 cache size. This speeds up import tremendously:

 {{{
 r.in.gdal ...
 memory=integer
     Maximum memory to be used (in MB)
     Cache size for raster rows
     Options: 0-2047
     Default: 300
 }}}

 I wonder how to get that into r.external (I suppose that it would benefit
 as well).

 > If options are needed for reading, a similar option should be added to
 both r.in.gdal and r.external, presumably using GDALOpenEx() instead of
 GDALOpen(). The latter will require extending the GDAL "link" format
 (lib/raster/gdal.c).

 OK (no idea how to implement that).

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/2428#comment:3>
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