Ways of compressing files and directories include:
|zip||.zip||This compresses multiple files and directories into one directory. zip support is built into Windows Explorer (but note: viewing the contents of a zip archive is not the same as unpacking it.) Download the command version laszip.exe here or from... Older versions cannot handle files larger than 4GB.|
|7zip||.7z||This is much like zip.|
|laszip||.laz||As las point files can be large, Martin Isenburg was kind enough to write a special program to compress and uncompress themin ways customized to las formats. Compressed files are ususally 7-20% of their original size. Compressed files have a .laz extension. There is a one-to-one correspondence of las to laz files. Download laszip.exe here or from rapidlasso.|
|gzip||.gz||OBSOLETEThis gnu software was needed while we waited for the copyright on
LZW compression to run out.
.gz files match the input files one-to-one. Download gzip.exe
Warning to chrome users: Chrome may uncompress a .gz on the fly, but neglect to strip off the .gz extension.
|compress||.Z||OBSOLETE This unix program became a dinosaur when copyrights were enforced. Remember, Jack?|
|tar||.tar||OBSOLETE IN THIS CONTEXT This command is as old as unix. It combined files and directories without compressing. It was customary to tar a directory and then gzip, ususally through a pipe. For example: tar cf - acme.e00 wickersham.e00 | gzip -c > acwick.e00.tar.gz to compress or gunzip -c acwick.e00.tar.gz | tar -xf - to uncompress.|
|tiff||.tif||Nowadays, .tif and .png files are internally compressed. No further compression is required. Our .tif files are geotiffs, so GIS software will place them properly on a map. Some of our tifs are 8-bit grayscale images, but some are 32-bit floating-point data files which can be read only by GIS software or by matlab.|
|no compression||wget||The wget program can download entire directory trees, but it works best with indexed directories. We have started to index these directories. You can open the .html file corresponding to a directory. In some cases, you might want to download individual files, but you will probably follow the instructions for downloading the whole thing with wget.|