[OSM-dev] 'My first OSM experiences' - PDA Mapping software and the OSM mobile binary protocol

[Oliver Ford]

Hi everyone,

I started looking at/using OSM a few weeks ago with the aim of getting 
the UK map (~7M nodes, 900K ways) on my new iPAQ which I've almost 
finished porting linux to.

Firstly, I'd like to say the whole OSM project is pure genius and am 
very thankful for the work every last developer/contributor has done. 
I'd certainly like to give something back by helping out.

I spent most of the time looking at a few PDA apps that are already out 
there and trying to convert the UK planet extract to the required format 
for each app.

I wrote up what I found out as an e-mail but it was a bit long so I've 
put it on my user page ( http://wiki.openstreetmap.org/wiki/User:Oliford 
) as a sort of (subjective) review for anyone who's interested in PDA 
OSM use or interested in what working with the OSM data is like for a 
newbie.

The short(er) story...

Getting anything to handle the whole UK data without running out of 
memory, seg-faulting or falling over on invalid UTF-8 is hard work. In 
the end I used roadmap which converts from the OSM Mobile Binary (OSMMB) 
format and I've written my own C program which converts the whole UK XML 
extract to OSMMB in about a minute.

I'm considering writing my own PDA app (open source of course) which 
would work directly from the OSMMB tiled vector data, give a 
slippy/scrollable and zoomable interface like Roadmap's but also provide 
the place/street name lookup and routing on all loaded tile data. The 
newer proposal on the OSM wiki for the OSMMB seems to be well suited to 
this. Currently the whole of the UK ends up in a 100MB OSSMB file which 
is really quick to parse. I can slice it into tiles, linearly search it 
for street names etc in a few seconds on a machine it takes several 
minutes to do the same on the XML.

I have some thoughts about things like merging multiple tiles' data and 
routing across different tiles but there are still some things I don't 
quite understand about the format (the wiki pages are a bit confusing on 
what is actually decided and what are just ideas).

Is anyone actively working on the OSMMB format now that I could direct 
my questions at?

Thanks,

Oliver Ford
PS: Just as I'm signing this off I've stumbled over the 
'OSMbin(file_format)' wiki page. Is that format related to the OSM 
Mobile binary somehow? Is one more developed/used than the other, has 
one been abandoned?