[OSM-dev] Compression types in PBF Format

[Anthony]

On Wed, Dec 1, 2010 at 12:40 PM, Scott Crosby <scrosby at cs.rice.edu> wrote:
> The 15% gain you measured between .rawpbf.xz and .pbf  really lets
> lzma cheat too much, because it can exploit a window tens of times
> larger than it would if integrated.

I'm not sure how much that mattered.  xz -3, which I believe uses a 1
megabyte window, still compresses to 63M.

> Could you run your test on a whole planet,

Not today.  I'm due to receive my new hard drives today, which I
bought last friday, so my filesystem is in complete disarray.  I'm not
even sure which drive/partition I have my whole planet file on, at the
moment.  I'm sure whatever partition it is, it isn't currently
mounted.

> or a hack-integration of LZMA into osmosis?

That I can definitively say I'm not going to do.  I'd sooner reverse
engineer the pbf format in C than mess around with the code of
osmosis.  It took me long enough just to figure out how to install the
right jre to get osmosis to run.