[GRASS-dev] [GRASS GIS] #2750: LZ4 when writing raster rows; better than double I/O bound r.mapcalc speed

[GRASS GIS]

#2750: LZ4 when writing raster rows; better than double I/O bound r.mapcalc speed
--------------------------+---------------------------
  Reporter:  sprice       |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  normal       |  Milestone:  7.2.0
 Component:  Raster       |    Version:  svn-trunk
Resolution:               |   Keywords:  ZLIB LZ4 ZSTD
       CPU:  OSX/Intel    |   Platform:  MacOSX
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Comment (by neteler):

 For the record - concerning NULL file compression:

 At time `cell_misc/null` is uncompressed by default.

 Using the environment variable `GRASS_COMPRESS_NULLS=1` NULL compression
 is activated for the session for newly created raster maps; and

 {{{
 export GRASS_COMPRESS_NULLS=1
 r.null -z raster_map
 }}}

 generates a new compressed file `cell_misc/nullcmpr` and removes the old
 uncompressed `cell_misc/null` file for existing maps.

 Note: At least GRASS GIS 7.2 is needed to read a raster map with
 compressed null file.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2750#comment:54>
GRASS GIS <https://grass.osgeo.org>