[OSM-dev] Optimal free compression algorithm for OSM XML data

Nick Hill nick at nickhill.co.uk
Thu May 10 15:53:39 BST 2007


Hello Shaun

Thank you for the pointers for Mac users and 7-zip.

I have uploaded a copy of the current planet.osm as 7z, where I have further 
increased compression using bigger dictionary etc.

planet files are at:
http://planet.openstreetmap.org/

The URL for the current planet.osm in 7z format is:
http://planet.openstreetmap.org/planet-070509.osm.7z

The new file is 183Mb vs Bzip2 235Mb.

You should find both downloading and unpacking the new file faster. Please try 
it and give feedback.

Shaun McDonald wrote:
> 
> On 10 May 2007, at 10:38, Nick Hill wrote:
> 
>> Hello David
>>
>> I'll upload a 7z version of the current planet. If nobody finds 
>> serious problems
>> with 7-zip, then I'll update the planet creation script to use 7z 
>> instead.
> 
> If I remember correctly, you need to install something special to get 
> 7-zip to compress/uncompress under Mac OS X. The command line version is 
> unfortunately a PPC app, which means that there is a performance hit on 
> Intel Macs.
> 
> My search history show that it was:
> <http://www.versiontracker.com/dyn/moreinfo/macosx/27156>
> It seems that a new version with a GUI and Universal is available at:
> <http://sixtyfive.xmghosting.com/?p=142> though it doesn't have a 
> command line interface as far as I can see.
> 
> I have one installed:
>  $ which 7za
> /usr/local/bin/7za
> $ 7za
> 
> 7-Zip (A) 4.20  Copyright (c) 1999-2005 Igor Pavlov  2005-05-30
> p7zip Version 4.20 (locale=C,Utf16=off,HugeFiles=on)
> 
> Usage: 7za <command> [<switches>...] <archive_name> [<file_names>...]
>        [<@listfiles...>]
> 
> Hope this is of some help to some Mac users out there.
> [..]
> Shaun
> 




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