Gents,<br><br>I am responsible for the openBmap website: <a href="http://www.openbmap.org">http://www.openbmap.org</a><br><br>As mentioned on the main page<br>"openBmap is a free and open map of wireless communicating objects <br>
(e.g. cellular antenna, Wi-Fi, Bluetooth). It provides tools to mutualize data, <br>create and access this map. "<br><br>At this time, only cellular networks are concerned.<br>All the software code is AGPL v3 and data are Creative Commons License <br>
(creative commons Attribution-Share Alike 3.0 Unported)<br><br>This site is quite similar to the <a href="http://opencellid.org">opencellid.org</a> website<br>(and I am currently merging the opencellid data into the openbmap database)<br>
<br>I identify tow main differences between <a href="http://openbmap.org">openbmap.org</a> and <a href="http://opencellid.org">opencellid.org</a> sites:<br><br>1) the way the coordinates of cells are calculated.<br><br>I am not using a simple barycenter method but the following method:<br>
<br>For a set of gps points concerning a cell, I identify the gps points which belong<br>to the envelope of the cell zone. After that I use the barycenter method on these points.<br><br>This method is not perfect but it works fine and can be much more precise than a simple<br>
barycenter method.<br><br>For each cell zone, I generate a kml file. This is nice to see how cells enveloppe and <br>how coordinates have been generated.<br><br><a href="http://realtimeblog.free.fr/cell_map.php?mcc=208&mnc=1&lac=1024&cellid=55608&display=Display">http://realtimeblog.free.fr/cell_map.php?mcc=208&mnc=1&lac=1024&cellid=55608&display=Display</a><br>
<br><a href="http://realtimeblog.free.fr/kml/cell_208_1_1024_55608.kml">http://realtimeblog.free.fr/kml/cell_208_1_1024_55608.kml</a> in google earth<br><br><br>2) the openBmap database contains much more information than opencellid one.(for raw data<br>
and for processed zone data)<br><br>We are keeping track of all attributes available such as:<br><br>*** gsm signal strength <br>*** quality of gps received<br>...<br><br>These attributes are not available in opencellid database. From these "extra" datas, <br>
we can for example decide to use only gps data of correct quality (with low vdop, hdop, hdop)<br><br>About the Android solution, the main drawbacks I see:<br>*** you must always be connected to get GPS coordinates from mcc/mnc/lac/cid.<br>
*** the cell database is not complete (tested from France, Paris suburb)<br><br><br>On our side, we plan to introduce an offline mcc/mnc/lac/cid->gps database.<br>but at this time, only one api is available at<br><a href="http://realtimeblog.free.fr/api/getGPSfromGSM.html">http://realtimeblog.free.fr/api/getGPSfromGSM.html</a><br>
<br>What is interesting with this api is that if the cell is not in the database, it returns<br>the lac position and the max radius of the lac<br><br>For your information I have implemented a reverse geocoding in the Mapping Manager<br>
in order to get the name of the city where the cell coordinates points at. <br><br><br>About openBmap client side, as you can see on the web site, a windows mobile version<br>is available. It logs mcc/mnc/lac/cid/signal strength and gps data. <br>
<br>The openmoko version is almost ready ! <br>The gsm/gps capture is ready and I guess it will be soon out.<br>The developer in charge will post soon on this thread.<br><br>Of course, I am here to provide you with all the information you need.<br>
(and to change API if needed...)<br><br><br>kind regards,<br>Nick<br><br><div class="gmail_quote">2009/1/12 Stefan Monnier <span dir="ltr"><<a href="mailto:monnier@iro.umontreal.ca">monnier@iro.umontreal.ca</a>></span><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">> I'm just curious how much this is built into the Android code. If any<br>
> Android phone can call the mothership to get the information, why<br>
> shouldn't we be able to do that? There are unlocked Andorid phones on<br>
> sale - do they have cell-based positioning disabled??? I would wager<br>
> that it isn't.... So what is the limit if is in the Android code?<br>
> Phones sold by Google? Phones supported with Android? Any phone<br>
> running Android? Any phone running an OS based on Android?<br>
<br>
Think about it: the provider cannot reliably tell if your phone logs<br>
this data or not. So if you write your own code that does that, they'll<br>
never know, so even if their contract doesn't allow you to do it,<br>
they'll never be able to enforce it (and won't even try, I'd guess).<br>
If Google distributes an OS that does that, the providers will know, so<br>
Google has to arrange some contract with them, to avoid prosecution.<br>
<br>
The providers don't care about individual uses, only about the<br>
larger picture.<br>
<br>
So, it's OK to write and distribute such code for the FR, but if OM<br>
starts distributing it they may be exposing themselves, although they're<br>
probably marginal enough that it doesn't matter much (yet).<br>
<br>
<br>
Stefan<br>
<br>
<br>
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</blockquote></div><br>