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

GRASS GIS trac at osgeo.org
Thu Mar 3 04:08:19 PST 2016

#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:  7.1.0
 Component:  Raster       |    Version:  svn-trunk
Resolution:               |   Keywords:  ZLIB LZ4 ZSTD
       CPU:  OSX/Intel    |   Platform:  MacOSX

Comment (by mlennert):

 Replying to [comment:50 mmetz]:
 > Replying to [comment:49 neteler]:
 > > Replying to [comment:48 mmetz]:
 > > > In your opinion:
 > > > * Adding new compression methods in G71 for cell/fcell files that
 are not readable by G70 is ok.
 > >
 > > No. If the format is broken, we need to call it G8 and provide
 > If we call it G8, converters are not needed because trunk as it is now
 can read G7 and G6 rasters.
 > Assuming trunk should be released as G7.1:
 > For full compatibility of relbr70 with trunk, not only read support for
 compressed null files would need to be backported, but also and more
 importantly read support for compressed cell/fcell files. These are new
 features at library level involving quite a few changes.

 -1 to backporting. Only bug fixes should go into relbr70.

 > The current default settings in trunk are compatible with relbr70, and I
 do not see a reason to change the respective default settings in trunk.

 +1, as long as the default settings lead to compatible maps, then I do not
 think any backporting is needed.

 >What exactly is the reason why null file compression should be enabled by
 default in >trunk?

 Again +1. I don't understand all the effects and issues involved, but null
 file compression seems to be something that is mostly needed for specific
 big data situations. People dealing with such situations can alter
 specific settings.

 > I will not backport the changes I did to trunk with regard to cell/cell
 file and null file compression because these are new features which should
 IMHO not go into an existing release branch.


 > Someone else would need to do the backporting.

 Please don't.

Ticket URL: <https://trac.osgeo.org/grass/ticket/2750#comment:51>
GRASS GIS <https://grass.osgeo.org>

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