[GRASS-user] Raster map - unsupported compressor error

GRASS GRASS user
1

Dear List,

I am running MacOS High Sierra (10.13.6) and have been using various versions of Grass GIS. Recently, I prepared raster maps using 7.8.3 but these maps do not open in lower versions of Grass such as 7.2.2. Higher versions like 7.9 open the same raster images without a problem.

I am getting the error below:

I will greatly appreciate any advice on fixing this issue for pre 7.8 versions of Grass.

Thank you!

BÜLENT ARIKAN

2

Newer versions of GRASS use, by default, the ZSTD compressor. But, I believe that older versions only support the simpler ZLIB.
See here for details:
https://grass.osgeo.org/grass78/manuals/rasterintro.html

In particular:
“All GRASS GIS raster map types are by default ZSTD compressed if available, otherwise ZLIB compressed. Through the environment variable GRASS_COMPRESSOR the compression method can be set to RLE, ZLIB, LZ4, BZIP2, or ZSTD.”

So to make rasters in 7.8 and have them available in 7.2 you will need to set the GRASS_COMPRESSOR environment variable in advance to “ZLIB” before creating the rasters in version 7.8. THen those should be readable in older versions.

(attachments)

Screen Shot 2020-07-23 at 1.42.45 PM.jpg

···

On 7/23/2020 3:41 PM, Bulent Arikan wrote:

Dear List,

I am running MacOS High Sierra (10.13.6) and have been using various versions of Grass GIS. Recently, I prepared raster maps using 7.8.3 but these maps do not open in lower versions of Grass such as 7.2.2. Higher versions like 7.9 open the same raster images without a problem.

I am getting the error below:

I will greatly appreciate any advice on fixing this issue for pre 7.8 versions of Grass.

Thank you!

BÜLENT ARIKAN

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-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
+972-523-665918
3

ceturtd., 2020. g. 23. jūl., plkst. 16:01 — lietotājs Micha Silver
(<tsvibar@gmail.com>) rakstīja:

So to make rasters in 7.8 and have them available in 7.2 you will need to set the GRASS_COMPRESSOR environment variable in advance to "ZLIB" before creating the rasters in version 7.8. THen those should be readable in older versions.

You can also use r.compress in 7.8 to recompress existing maps with
different compression algorithm (ZLIB). A good idea to save some disk
space taken by old maps.
https://grass.osgeo.org/grass78/manuals/r.compress.html

Māris.

P.S. Why do you want to use 7.2 if 7.8 is working fine on your system?