#2750: LZ4 when writing raster rows; better than double I/O bound r.mapcalc
speed
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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
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Comment (by wenzeslaus):
Replying to [comment:26 mmetz]:
> Data for the null2 file are now compressed with the same method like
actual raster values. Because NULL data usually occur in long sequences of
identical values, the new generic RLE algorithm I wrote for
lib/gis/compress.c seems to perform best (highest compression, very fast).
However, for consistency it would be better to use the same compressor for
both the null bitsream and the raster data.
For advanced users it seems that different compression for FCELL+DCELL and
for NULL+CELL would make sense. If I have a MODIS LST for an island, then
I want to use RLE for NULL files but BZIP2 for DCELL.
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Ticket URL: <https://trac.osgeo.org/grass/ticket/2750#comment:31>
GRASS GIS <https://grass.osgeo.org>
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