[OSM-dev] Compression types in PBF Format

Jochen Topf jochen at remote.org
Tue Nov 30 11:33:24 GMT 2010

On Tue, Nov 30, 2010 at 10:58:40AM +0100, Stefan de Konink wrote:
> On Tue, 30 Nov 2010, Tim Teulings wrote:
>> Hallo!
>>> Why this mentality? It is trivial to implement a decompression 
>>> algorithm and some work better than others. Sounds like complaining 
>>> about stuff you don't have to care about.
>> I would not implement decompression myself, I have better things to do. 
>> Thus I would a library for this. A library however is a dependency, 
>> that must be build installed and delivered (not all the world runs 
>> Linux with smart packaging systems) and licences have to be checked. It 
>> makes sense for teh developer to try to reduce such dependencies by 
>> agreeing on one standard compression format.
> Since all program interfaces virtually equal gzip, and it gives perfect  
> extendability. The choose for supporting the 3 most used compression  
> schemes is perfectly sound.
> Stop wining about code that either you do not write, or didn't care about 
> before. There was this great moment when the bitstream was defined, and  
> absolutely nobody cared until people started to write pbf code.

Stefan, I do not like your tone here. It wouldn't kill you to be a bit
more civilized to people.

I wouldn't have asked this question if I wasn't working on PBF code. I do care
about my code. I do care that it seems I am writing code that might never be
used. I want to test the code that I am writing. Do you have code that actually
writes PBF files in all those encodings? From the documentation I found on the
wiki it seems that Osmosis doesn't.

Those are perfectly reasonable questions. I don't mind writing code thats
actually useful. But I do mind spending time on code that isn't.

So lets get back to the subject: Is anybody writing PBF files with anything but
zlib compression? Do we need more compression types? If yes, would that be an
option to the writer program or is the writer somehow supposed to figure out
what the best compression is?

Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298

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