64 | | * libraster: support for new raster data compression methods: |
| 74 | * libraster: support for new raster data compression methods: NONE, ZLIB, LZ4, BZIP2. Overview: |
| 75 | * Raster map compression set by `export GRASS_COMPRESSOR=XXX`, with XXX be |
| 76 | * `NONE` (uncompressed) |
| 77 | * `RLE` (generic Run-Length Encoding of single bytes) |
| 78 | * `ZLIB` (DEFLATE, good speed and compression) |
| 79 | * with zlib compression levels (`export GRASS_ZLIB_LEVEL=X`): -1..9 (-1 is default which is level 6) |
| 80 | * Notes: ZLIB level = 0 tells ZLIB to copy the data as-is from source to destination. In case of CELL maps, the rasterlib itself will then still trim high zero bytes with trim_bytes() which can already reduce the data size considerably, but ZLIB will not compress the data. |
| 81 | * `LZ4` (fastest, low compression) |
| 82 | * `BZIP2` (slowest, high compression) |
| 83 | * NULL file compression: At time it must be explicitly turned on with `export GRASS_COMPRESS_NULLS=1` |