[GRASS-SVN] r74115 - in grass/branches/releasebranch_7_6: lib/init raster raster/r.compress
svn_grass at osgeo.org
svn_grass at osgeo.org
Wed Feb 20 12:43:02 PST 2019
Author: mmetz
Date: 2019-02-20 12:43:01 -0800 (Wed, 20 Feb 2019)
New Revision: 74115
Modified:
grass/branches/releasebranch_7_6/lib/init/variables.html
grass/branches/releasebranch_7_6/raster/r.compress/r.compress.html
grass/branches/releasebranch_7_6/raster/rasterintro.html
Log:
update documentation with regard to ZSTD as default compression if available, see #3758 (backport trunk r74114)
Modified: grass/branches/releasebranch_7_6/lib/init/variables.html
===================================================================
--- grass/branches/releasebranch_7_6/lib/init/variables.html 2019-02-20 20:39:39 UTC (rev 74114)
+++ grass/branches/releasebranch_7_6/lib/init/variables.html 2019-02-20 20:43:01 UTC (rev 74115)
@@ -111,8 +111,12 @@
<dd>[libraster]<br>
the compression method for new raster maps can be set with the
environment variable GRASS_COMPRESSOR. Supported methods are RLE,
- ZLIB, LZ4, BZIP2, and ZSTD. The default is ZLIB which can be
- changed with e.g. <tt>GRASS_COMPRESSOR=ZSTD</tt></dd>
+ ZLIB, LZ4, BZIP2, and ZSTD. The default is ZSTD if available,
+ otherwise ZLIB, which can be changed with e.g.
+ <tt>GRASS_COMPRESSOR=ZSTD</tt></dd>, granted that GRASS has been
+ compiled with the requested compressor. Compressors that are always
+ available are RLE, ZLIB, and LZ4. The compressors BZIP2 and ZSTD
+ must be enabled when configuring GRASS for compilation.
<dt>GRASS_DB_ENCODING</dt>
<dd>[various modules, wxGUI]<br>
Modified: grass/branches/releasebranch_7_6/raster/r.compress/r.compress.html
===================================================================
--- grass/branches/releasebranch_7_6/raster/r.compress/r.compress.html 2019-02-20 20:39:39 UTC (rev 74114)
+++ grass/branches/releasebranch_7_6/raster/r.compress/r.compress.html 2019-02-20 20:43:01 UTC (rev 74115)
@@ -15,11 +15,11 @@
<p>
During compression or re-compression, <em>r.compress</em> compresses
raster maps using the method specified by means of the environment
-variable <tt>GRASS_COMPRESSOR</tt>. The default compression method is
-ZLIB's "deflate" algorithm (LZ77-based). Raster maps that contain very
-little information (such as boundary, geology, soils and land use maps)
-can be greatly reduced in size. Some raster maps are shrunk to roughly
-1% of their original sizes.
+variable <tt>GRASS_COMPRESSOR</tt>. The default compression method is
+ZSTD if available, otherwise ZLIB's "deflate" algorithm (LZ77-based).
+Raster maps that contain very little information (such as boundary,
+geology, soils and land use maps) can be greatly reduced in size. Some
+raster maps are shrunk to roughly 1% of their original sizes.
All newly generated raster maps are automatically stored as compressed
data with varying methods depending on the raster format (i.e.,
CELL: integer; FCELL: single precision; DCELL: double precision; see
@@ -101,10 +101,10 @@
<h3>COMPRESSION ALGORITHM DETAILS</h3>
<!-- keep in sync with raster/rasterintro.html -->
-All GRASS GIS raster map types are by default ZLIB compressed, i.e. using
-ZLIB's deflate algorithm. Through the environment variable
-<tt>GRASS_COMPRESSOR</tt> the compression method can be set to RLE, ZLIB,
-LZ4, BZIP2, or ZSTD.
+All GRASS GIS raster map types are by default ZSTD compressed if
+available, otherwise ZLIB compressed. Through the environment variable
+<tt>GRASS_COMPRESSOR</tt> the compression method can be set to RLE,
+ZLIB, LZ4, BZIP2, or ZSTD.
<p>
Integer (CELL type) raster maps can be compressed with RLE if
the environment variable <tt>GRASS_COMPRESSOR</tt> exists and is set to
@@ -115,6 +115,9 @@
<!-- BTW, why not having an option "method" and another one "level"
instead of the environment variables? Is it too complicated?
+
+ Where should these options "method" and "level" be available/
+ exposed to the user? Surely not in every module creating a raster map.
-->
<dl>
<dt><strong>RLE</strong></dt>
Modified: grass/branches/releasebranch_7_6/raster/rasterintro.html
===================================================================
--- grass/branches/releasebranch_7_6/raster/rasterintro.html 2019-02-20 20:39:39 UTC (rev 74114)
+++ grass/branches/releasebranch_7_6/raster/rasterintro.html 2019-02-20 20:43:01 UTC (rev 74115)
@@ -279,9 +279,10 @@
<h3>Raster compression</h3>
<!-- keep in sync with raster/r.compress/r.compress.html -->
-All GRASS GIS raster map types are by default compressed. Through the
-environment variable <tt>GRASS_COMPRESSOR</tt> the compression method
-can be set to RLE, ZLIB, LZ4, BZIP2, or ZSTD.
+All GRASS GIS raster map types are by default ZSTD compressed if
+available, otherwise ZLIB compressed. Through the environment variable
+<tt>GRASS_COMPRESSOR</tt> the compression method can be set to RLE,
+ZLIB, LZ4, BZIP2, or ZSTD.
<p>
Important: the NULL file compression can be turned off with
<tt>export GRASS_COMPRESS_NULLS=0</tt>. Raster maps with NULL file
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