[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
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  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
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Comment (by neteler):

 Replying to [comment:16 glynn]:
 > How large are the null files compared to the cell/fcell files?

  * With MODIS LST data, the null files are between 1.7 and 7.6 times
 larger than the cell files (we store the LST maps in deg C * 100 as
 integer to save disk space).
  * With 100k random points, the null file is 7.1 times larger than the
 fcell map
  * With the EU 25m DEM, the null file is way smaller that the derived
 aspect map (17% of the DEM fcell file)

 > > What about having a "null2" file which is compressed and with index.
 If present, fine, otherwise use the uncompressed well known null file
 format?
 >
 > That's probably not a great deal of work, but as with any such change,
 we need to consider the migration strategy. If we just start creating
 compressed null files, mapsets will cease to be usable with older
 versions.

 Right but this could be covered with an addon/new script in G6 and earlier
 (as v.build does for vector data).

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2349#comment:17>
GRASS GIS <http://grass.osgeo.org>