[GRASS-dev] [GRASS GIS] #2349: CELL raster format: make ZLIB level 3 standard compression instead of RLE

[GRASS GIS]

#2349: CELL raster format: make ZLIB level 3 standard compression instead of RLE
--------------------------+-------------------------------------------
  Reporter:  neteler      |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  critical     |  Milestone:  7.1.0
 Component:  Raster       |    Version:  svn-trunk
Resolution:               |   Keywords:  compression, r.compress, null
       CPU:  Unspecified  |   Platform:  All
--------------------------+-------------------------------------------

Comment (by neteler):

 Thanks for the patch. I applied it to my local copy of relbr70. Testing
 with this map

 {{{
 GRASS 7.0.1svn (eu_laea):~/releasebranch_7_0 > r.info -g eu_dem25_rand100k
 north=6000000
 south=1000000
 east=8000000
 west=2000000
 nsres=25
 ewres=25
 rows=200000
 cols=240000
 cells=48000000000
 datatype=FCELL
 ncats=0
 }}}

 I created a new one using the 100k random points FCELL map sampled earlier
 from the EU 25m DEM:

 {{{
  r.mapcalc "new = eu_dem25_rand100k"
 }}}

 Using the patch, I see that a NULL file is no longer generated.
 Expectedly, since the other modules are not updated yet, I cannot read
 that map:

 {{{
 GRASS 7.0.1svn (eu_laea):~/releasebranch_7_0 > r.univar new
 ERROR: Raster map <new at PERMANENT>: format field in header file invalid
 }}}

 Next test with INT conversion:


 {{{
 GRASS 7.0.1svn (eu_laea):~/releasebranch_7_0 > r.mapcalc "new_int =
 round(eu_dem25_rand100k)"

 GRASS 7.0.1svn (eu_laea):~/releasebranch_7_0 > r.univar new_int
 0%
 }}}

 ... the map is readable and comes with the NULL file but that's as before
 6GB big (so no compression occurred).

 Are my tests wrong or am I missing anything else?

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2349#comment:19>
GRASS GIS <http://grass.osgeo.org>