[OSM-dev] Call to mobile developers: OSM binary file format

Ævar Arnfjörð Bjarmason avarab at gmail.com
Thu Aug 7 14:07:11 BST 2008


On Thu, Aug 7, 2008 at 8:32 AM, Chris Browet <cbro at semperpax.com> wrote:
> We all have the same problem: the XML OSM format is not efficient for mobile
> devices.
> For the time being, we all develop our own solution to transform the XML in
> whatever binary format suitable for a mobile application, often forcing the
> user to use a specific desktop application for the transformation.
>
> I would like to know if some of you would be interested in developing a
> common binary format, rather than each application having its own,
> incompatible with the others.

Different devices will have different optimization needs. If you're
optimizing your binary format for a given device you'll almost always
end up doing something device specific rather quickly, like padding
the integers in your format to the device's native integer size, or
arrange it to be little or big endian depending on the processor.

Furthermore different devices may actually require something different
out of an OSM xml  dump, some devices may have no concept of
relations, or ways to name a less likely example.

There's a reason people use XML, it's an interchange format but binary
formats aren't, they're meant for specific architectures or purposes.

Which is not to say a discussion like this one isn't useful, you'll
probably get all sort of ideas from different embedded developers. But
I for one would be very surprised if every embedded developer would
end up using the same binary format.




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