[OSM-dev] Release of osmpbf version 1.2.1

Scott Crosby scott at sacrosby.com
Mon Oct 31 23:06:39 GMT 2011


On Mon, Oct 31, 2011 at 9:31 AM, Jochen Topf <jochen at remote.org> wrote:
> On Mon, Oct 31, 2011 at 10:31:11AM +0100, marqqs at gmx.eu wrote:
>> > * Includes support for "visible" flag on OSM objects. This allows PBF to
>> >   handle OSM history files.
>>
>> Great! Thank you - and Jochen.
>>
>> Could you please, if possible, update the OSM Wiki page accordingly?
>> Last time I needed to analyze an .osh.pbf file's contents byte by byte to see how the visible flag was stored. That was really fun for me, but not everyone likes this kind of riddle. ;-)

How much benefit do you get from reading the raw bytes this way,
versus going through google protobuf? The decoding loop of osmconvert
scares me a bit. The reason I chose protobuf was to *avoid* anyone,
including myself, from having to implement their own serialization
code.

>
> This information is in the .proto files. I have added the section of the proto
> file that was missing to the wiki page. But I do agree that the documentation
> is not as good as it could be. Still far better than many other parts of OSM.
> :-)

A binary format definitely needs to be documented very well, but I
admit that my main documentation was for the decoder. I was following
the philosophy that as long as the specification is sufficiently
precise to fully specify interoperable decoders, the exact encoder
implementation is an implementation detail.

>
> What I'd like to see at some point is a better distinction between the PBF
> format itself and the reference (and other) implementations.
>

What kind of things were you thinking of?

Also, if we're talking about PBF, do we want to open a conversation
about OSM metadata, in both the PBF and XML formats?

Scott



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