[GRASS-SVN] r52408 - grass/trunk/raster/r.compress

[svn_grass at osgeo.org]

Author: neteler
Date: 2012-07-19 02:30:51 -0700 (Thu, 19 Jul 2012)
New Revision: 52408

Modified:
   grass/trunk/raster/r.compress/r.compress.html
Log:
explain RLE and zlib

Modified: grass/trunk/raster/r.compress/r.compress.html
===================================================================
--- grass/trunk/raster/r.compress/r.compress.html	2012-07-19 09:29:54 UTC (rev 52407)
+++ grass/trunk/raster/r.compress/r.compress.html	2012-07-19 09:30:51 UTC (rev 52408)
@@ -82,6 +82,15 @@
 automatically used when new raster map layers are
 created).
 
+<p>
+RLE compression versus zlib compression: if the environment variable
+GRASS_INT_ZLIB exists, new raster maps will be compressed using zlib 
+instead of RLE compression. In the cellhd file, the value for
+"compressed" is 1 for RLE and 2 for zlib.
+<br>
+Obviously, decompression is controlled by the raster's "compressed"
+header value, not the environment variable.
+
 <h4>PRE-3.0 FORMAT:</h4> 
 
 First 3 bytes (chars) - These are a special code that identifies