[GRASS5] 5.4 release branch
glynn.clements at virgin.net
Tue Oct 12 17:17:47 EDT 2004
Markus Neteler wrote:
> > Here is my first rough draft of what to put in the NEWS file for 5.4.0,
> > additions and corrections welcome:
> > Raster I/O re-write incorporating support for files > 2GB (Glynn)
> Probably it should become a flag for 'configure' (maybe that is already?)?
I'm not sure about the right way to implement this. Ideally, it should
only be the core raster I/O files which I changed which should be
using the large-file support, as the rest of GRASS won't handle large
One possibility is to make configure define a macro, e.g.
RASTER_LARGEFILE, in config.h, and have the files in question do:
#define FILE_OFFSET_BITS 64
before including any other headers. But that seems a bit messy.
> > Support for zlib compression in integer/CELL maps (Glynn)
> How to activate it?
If the environment variable GRASS_INT_ZLIB exists, new compressed
rasters will be compressed using zlib instead of RLE compression. Such
rasters will have a "compressed" value of 2 in the cellhd file.
Obviously, decompression is controlled by the raster's "compressed"
value, not the environment variable.
> Is that documented?
> > g.pnmcomp: Added (Glynn)
> Is it documented?
It's intended for internal use only, if at all. It composes a set of
PPM/PGM files (where a PGM file contains the alpha channel for a
specific PPM file) into a single PPM file.
The idea is to consider using it in d.m, in conjunction with the PNG
driver. d.m would render each layer as a PPM/PGM pair (the PNG driver
will generate these if $GRASS_PNGFILE ends in ".ppm" and
$GRASS_TRANSPARENT is "TRUE").
If the layer stack is changed (enabling or disabling layers, changing
the ordering), d.m would only need to re-compose the
(already-rendered) PPM/PGM files, which is much faster than
re-rendering everything using the d.* programs.
This assumes that d.m would be displaying the composed image itself
(in a Tk widget) rather than via XDRIVER.
> > r.colors new format for rules files (Hamish, Glynn)
> Is there a possibility to make the parser (a function) list the
> available color files? Such as the 5.7 db.* tools list the available DB
Can you elaborate?
Glynn Clements <glynn.clements at virgin.net>
More information about the grass-dev