There are two types of compression:
- Lossless. If you cannot tolerate changes in the data, it
must be lossless. Some kinds of files, like text, can still get very
good compression. Examples include the DOCX and PPTX formats for
Microsoft Office, or the LAZ format for Lidar point clouds which reduces
file sizes to 10-20% of the original.
- Lossy. If you are willing to trade some data quality for
additional compression, lossy compression works. Examples include
DVDs, MP3 and other music formats, and JPEG photos. Mapping examples
include MrSid or JPEG2000.
Compression of GIS data often uses standard Windows ZIP compression, but often
uses Unix TAR and GZIP.
Last revision 3/27/2014