LAZ format is identical to LAS except for being compressed. LAZ format is popular for publishing LiDAR data because LAZ files are usually many times smaller than LAS files. A 450 MB LAS file, for example, will often compress to a LAZ file that is well under 60 MB. The price we pay for smaller file sizes is that for general purpose GIS work LAZ format must be decompressed to recover the original LAS data, at least into memory cache or temporary working files. Decompression is fast, but nonetheless significant time, possibly tens of seconds per file, is required to decompress bigger LAZ files.