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.7zThis is much like zip.
laszip.lazAs 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 origianl size. Compressed files have a .laz extension. There is a one-to-one correspondence of las to laz files. Download laszip.exe or the laszip-cli.exe (command-line version here or from rapidlasso.
gzip.gzOBSOLETEThis 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.ZOBSOLETE This unix program became a dinosaur when copyrights were enforced. Remember, Jack?
tar.tarOBSOLETE 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.tifNowadays, .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 compressionwget 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.

Join the fray

Lately we have been experimenting and tussling over the best way to post files for download. (Yes, we know that there is more to the web than file downloads. We hope to eventually have a gis server and/or image server. Map servers too? Who knows.) But how do you like our files? Some answers will vary for raster and point data.
Any other concerns?
We apologize for the fact that a shape files is not a single file.
Write with your concerns to Drew and Harvey. Or should we start a blog?

draft 9/30/2016