[OSM-dev] [OSM-newbies] URL for mobile binary protocol

Martijn Pannevis openstreetmap at panman.nl
Thu Mar 20 13:50:45 GMT 2008


Milo, I think you don't really understand the issue.
You can EITHER use tiles, which are relatively big to transfer and store 
(but is the current solution I use), Or you can download the vector 
data, which is smaller, but needs to be rendered, which would take a 
mini-mapnik.
Greetings,
Martijn Pannevis.

Milo van der Linden wrote:
> I know that Rob (Rubke) wrote a tool that is called OSMtiledownloader.
> http://wiki.openstreetmap.org/index.php/OSMtiledownloader
> It allows you to download tiles to the desktop given a certain 
> directory structure. This directory can then be copied to a mobile 
> device and used in conjunction with OSMTracker
> http://wiki.openstreetmap.org/index.php/Osmtracker
>
> This solves the issue of complex rendering, and give you a base set of 
> tiles. OSMtracker also has a live tile download function, but it is 
> not the fastest around yet.
>
> So I disagree that you would need a mini mapnik on your mobile. I 
> think it might be good to build a standard API to handle rendering 
> tiles based upon a certain directory structure and a download API for 
> getting tiles into your phone via GPRS. The both combined will 
> probably require less processing power then setting up a mapnik server 
> on the phone.
>
> Martijn Pannevis schreef:
>> Robert (Jamie) Munro wrote:
>>   
>>> -----BEGIN PGP SIGNED MESSAGE-----
>>> Hash: SHA1
>>>
>>> Jason Dent wrote:
>>> | I have a mobile map application.  I have found that directly accessing the
>>> | tile server works the best.
>>>
>>> The downloads are HUGE! Some people have to pay per kB for mobile
>>> downloads. Also, you can't rotate and reproject the tiles, or give a
>>> sat-nav type 3d view, without horribly distorting the text. If you want
>>> to highlight a road or a point, you have to download the map details anyway.
>>>
>>> | Trying to draw all the map details at runtime
>>> | on a PDA is a bit much.  It can be done, but pre-cooked tile are much
>>> | better.
>>>
>>> It's not "a bit much". *All* commercial sat-navs do it. When you
>>> consider how much more CPU power a modern PDA has than a PC of 15 years
>>> ago, and think about the kind of thing those PCs did (Doom, for example)
>>> drawing a map is easy.
>>>     
>> I agree that technically redering tiles on the mobile probably would be 
>> the best solution, certainly in terms of data traffic.
>> However, to get nice looking tiles, you'd have to implement something 
>> like mapnik, on your device. I know it already took us quite some work 
>> to implement a nice map with scrolling tiles in J2ME. I'm sure building 
>> that with vectors, which scale with zoomlevels, and look nice, would 
>> take months, if not years, of development time. Thats why we choose to 
>> use tiles.
>> I do want to look into more efficient ways of getting tiles, or parts of 
>> them, to the mobile.
>> Kind Regards,
>> Martijn Pannevis.
>>
>>     





More information about the dev mailing list