OpenCellID (was OpenBmap logger (GSM positioning)])
Thomas Landspurg
t.landspurg at 8motions.com
Wed Aug 26 08:38:05 CEST 2009
Sorry for not replying this email. I am not an active member of the
open moko community so I was a little bit overloaded by the mail rate
at that time. Hopefully, the OpenVMap guy pointed me this unreplied
email, so here are my answer, and it's basically very short:
2009/2/21 Nick <realtimeblog at gmail.com>:
> Thomas,
>
> I agree with you about the train and people in the train.
> what about bad gps hdop,... ?
>
> I agree your approach will be probably enought for assited GPS.
> (anyone knows the precision needed ?)
>
> but I don't think this is the right one for the other services mentionned.
>
> Thinking of a high quality "my position" service (google kind),
> we will not achieve it not treating gps hdop, gps speed...
>
> so to be constructive in order to merge our databases,
> would you be ready to collect gps speed, gps (hvp)dop and make these
> info available
> in your (very large) measures file ?
YES
>
> From this, I could provide you with a new mapping manager that identify
> the cells position calculated with gps (hvp)dop, gps speed when these
> values are available
> the cells position calculated with no gps (hvp)dop, gps speed because
> these values are not available
>
> We would have only one database with both quantity (the whole database)
> and quality for some cells. (Hoping that the best quality,
> would be available for all the cells in the future)
>
> what do you think about it ?
>
Sounds great!
The diifculty will be to do the new computation of all cells with
data of various level of quality. Hard but not unpossible
> regards,
> Nick
>
> Thomas Landspurg a écrit :
>>
>>
>> 2009/2/20 Nick <realtimeblog at gmail.com <mailto:realtimeblog at gmail.com>>
>>
>> Thomas,
>>
>> After trying to reach you a few times last year,
>> i am really glad to have some news from you now.
>>
>>
>> The easiest way is to use the email mentionned in the Web page! ;-)
>>
>>
>>
>> I am reponsible for the openBmap website. And yes, it would be a great
>> thing to merge our projects !
>>
>> The number of logs you have is very impressive ! well done !
>>
>> My concern would be about the quality of your data .
>>
>> you still mention on the front page
>>
>> "Note:If you want a professional CellID Database, I suggest you to
>> go to
>> Navizon
>> who provides top services and databases."
>>
>> what do you mean ?
>>
>>
>>
>> Tihs mean that there are company that have created huge databases of
>> high quality by spendig a lot of money on it, and they make money by
>> selling these data. Navizon pays his users for this, and other are
>> throwing a lot of money on this too, by sending people doing measures,
>> or by buying operators database. That's exactly the same difference
>> between OpenStreetMap and Navteq/Teleatlas. OpenStreetMap is free,
>> provided by the community, but of a lower quality than their
>> commercial counterpart except on some specific area not covered by
>> these equivalents. Of course, the objective is to reach the same
>> quality, but this will take time.
>>
>>
>>
>>
>> and after importing 800 000 of your gps points in january, I see that
>> for instance
>> gps speed, gps hdop, gps pdop, gps vdop are not available
>> (at least at the begining of this huge measures.txt file !),
>>
>>
>> A bad pdop, vdop, hdop and i am positioned at 1 km from my real
>> position ...
>> What if i am in a high speed train at 300 km/h? or in plane ? (yes, it
>> can work in planes...)
>>
>>
>>
>> Let's go back to the basics: the objective of these database if to
>> provied an positionning to create services using localisation on top
>> of this database. Let's take the sample of an high speed train: there
>> is high chances that all the sample will came from people in the train
>> itself, and not from the neighbour outside (train don't go at 300 km/h
>> in high density area). So this mean that the REAL position of the cell
>> will never be accuratly computed, which is not an issue, because the
>> only interesting information is the user position. So sampling mesures
>> even some errors is fine as long as it works fine to get user position.
>> So the philosophy behing opencellid was to reach the 80/20 ratio:
>> acheiving the 80% of functionality will require only 20% of the time
>> needed to do these 100% functionality. So that's why we have a simple
>> and elegant API, that is used by different devices with different
>> capacities, while acheiving exactly this objective: providing an
>> accurate cell id positionning.
>>
>>
>>
>> In my opinion, considering the following services
>>
>> *** asisted gps
>> *** "cell id" to google "my position" kind of service
>> *** "cell id" to "town name" service
>>
>>
>>
>> the real questions are:
>> what precision do we need for openmoko location service through
>> gsm cell
>> id ?
>> what precision our possibly merged database would provide ?
>>
>>
>> Assisted GPS does not require huge precision. I am not an expert, but
>> I would be curious to know what is the precision needed to get an
>> assisted GPS. Using triangulation is a different story, and this
>> obvisouly will work fine only in high density area, where you also
>> have high density cells. So again, there is a direct correlation
>> between the precision and the density of the area.
>> Note also that OpenCellID use LAC (Local Area Code) to provide an
>> alternate positioning with a lower precision if a cell is not know,
>> but if the LAC is know. Typically other cells has been discovered in
>> the same area.
>> So once you get CellID positionning, you can use reverse geocoding
>> service to get the town for instance.
>>
>>
>>
>>
>> what do you think about the above considerations ?
>>
>> really glad to hear from you !
>>
>> regards,
>> Nick
>>
>> Thomas Landspurg a écrit :
>> >
>> >
>> > 2009/2/20 Onen <onen.om <http://onen.om>
>> <http://onen.om>@free.fr <http://free.fr> <http://free.fr>>
>> >
>> > Hi Thomas,
>> >
>> > Thomas Landspurg wrote:
>> > >
>> > > Dear OpenMoko community (and thanks ed for pointing this
>> out).
>> > >
>> > > I am behind the opencellid.org <http://opencellid.org>
>> <http://opencellid.org>
>> > <http://opencellid.org> project, and it
>> > > seems that there are some discussion around it these day
>> on the
>> > mailing
>> > > list.
>> > >
>> >
>> > Last month, and today, indeed.
>> >
>> >
>> > Yes, I've get to it today! It's a pity not to have been notified of
>> > such discussion before. I've been through them, and I want to
>> add some
>> > clarification about difference between database:
>> >
>> > - OpenCellID can also store signal strengh. But one of the issue, is
>> > heterogenity between datas. Some client don't have this information,
>> > and this create some additional complexity. That's why this
>> > information is for now only stored but not yet used. And in all was,
>> > if you want it, it's in the measure table, and not in the cell
>> table.
>> >
>> > - About the barycenter of the area/instead of barycenter: it's not
>> > always the best way to do it, as it give more value to false datas.
>> > while the "simple" barycenter reduce these. Another option would
>> be to
>> > exclude data that would be completely "out of range"
>> >
>> > And more "general" information about the databse: more than 500
>> > developers have registered to get an API key. Obvisouly not 500
>> > application are out, but show the interest of the community
>> >
>> >
>> >
>> >
>> > > So let me clarifiy:
>> > >
>> > > - As described in the web site, the license is under
>> creative common
>> > > share alike 3.0. I had several request today stating that just
>> > linking
>> > > to the license was not clear enough, so I will re-clarify
>> it on
>> > the web
>> > > site, but also in this list.
>> > >
>> >
>> > Last time I checked (and other people, see the post I
>> pointed out
>> > earlier today), it was not clear. But today, as people had a
>> look
>> > again,
>> > it seems to me pretty clear :-)
>> >
>> >
>> > Last time, it was written under creative common license, with a link
>> > to the creative common share alike license. I am sorry if this
>> was not
>> > clear enough, but as you see, a simple mail is enough to get it
>> corrected.
>> >
>> >
>> >
>> >
>> > > - I am surprised to see statment that I did not answer to some
>> > > questions. I've verified,and all openmoko request have been
>> > answered. I
>> > > am not perfect, and may be some emails have been missed, but a
>> > search on
>> > > openmoko on my mail box did not raise any pending question.
>> > >
>> >
>> > Not sure what you mean by openmoko request... When I stated that
>> > neither
>> > us nor openmoko did get an answer, I should have written:
>> "If I recall
>> > correclty openmoko tried to reach opencellid, but I have not
>> heard of
>> > any response. We tried to contact opencellid, but got no
>> response." I
>> > personally have not tried to reach you. But Nick yes,
>> without answer,
>> > for what I have understood.
>> >
>> >
>> > Would be curious to have his email just to check. I am quite sure
>> > I've answered to all demands like this.
>> >
>> >
>> > > There is more than 100 000 cells covered, with 5.5
>> millions of
>> > > measure, and more cells will be "donated" soon. We expect to
>> > reach 200
>> > > 000 cells in the coming weeks thanks to a new project
>> donation.
>> > There is
>> > > also more than 10 different clients (windows mobile, symbian,
>> > > blackberry, j2me,...) gathering the database.
>> > >
>> >
>> > Is there different countries?
>> >
>> >
>> > Yes, the stats page show all countries:
>> >
>> > http://www.opencellid.org/cell/stats
>> >
>> >
>> >
>> > Good to see there is no client for openmoko, otherwise I may
>> have
>> > worked
>> > for nothing ;-)
>> >
>> >
>> > Yes, I've heard that other where working on such client too!
>> >
>> >
>> >
>> > > I've been running this project since more than one year
>> , with an
>> > > objective to push community efforts around cell id. So I would
>> > be more
>> > > than happy to see new effort joining this project instead of
>> > creating
>> > > separate efforts. So let's join effort and create
>> something big!
>> > >
>> >
>> > I am very glad to read this, especially as I was very
>> disappointed not
>> > being able to leverage the existing work you have done. For
>> my part I
>> > work on the client side. A logger/uploader. I guess it would be
>> > easy to
>> > modify it to upload to your database if we go that way. But
>> for now, I
>> > think it would be good Nick (who takes care of the server side)
>> > and you
>> > keep discussing, in order to evaluate a possible merger.
>> >
>> > As there are also plans on embedding the database on the
>> phone, and
>> > using it to locate, I would like to know if this part would
>> interest
>> > you? Or only the server side and upload?
>> >
>> >
>> > The idea is to provide all the means to do so. So if there is
>> anything
>> > that is needed to help you to do this, I would be happy to
>> provide it.
>> > For instance, a way to send an area and get the list of cells in
>> that
>> > area. I amalready working on such functionality.
>> > But the switch to from OpenBMap to OpenCellID should be quite fast
>> > as I assume that the API is probably the same, or very close to. (
>> > http://www.opencellid.org/api )
>> >
>> >
>> >
>> > > And as a reminder, the complete data base is available for
>> > download.
>> > >
>> > > So if you have any question/interrogation, feel free to share
>> > them with
>> > > me so we can clarify this.
>> > >
>> > > Regards,
>> >
>> > Great we can move along. I hated this feeling of reinventing the
>> > wheel!
>> >
>> >
>> > So do I!
>> >
>> >
>> >
>> > Onen
>> >
>> >
>> > _______________________________________________
>> > Openmoko community mailing list
>> > community at lists.openmoko.org
>> <mailto:community at lists.openmoko.org>
>> <mailto:community at lists.openmoko.org
>> <mailto:community at lists.openmoko.org>>
>> > http://lists.openmoko.org/mailman/listinfo/community
>> >
>> >
>> >
>> >
>> > --
>> > Thomas LANDSPURG
>> > 8Motions
>> > Founder/CTO
>> > http://www.8motions.com
>> > http://www.opencellid.org
>> >
>> >
>> >
>> ------------------------------------------------------------------------
>> >
>> > _______________________________________________
>> > Openmoko community mailing list
>> > community at lists.openmoko.org <mailto:community at lists.openmoko.org>
>> > http://lists.openmoko.org/mailman/listinfo/community
>> >
>>
>> _______________________________________________
>> Openmoko community mailing list
>> community at lists.openmoko.org <mailto:community at lists.openmoko.org>
>> http://lists.openmoko.org/mailman/listinfo/community
>>
>>
>>
>>
>> --
>> Thomas LANDSPURG
>> 8Motions
>> Founder/CTO
>> http://www.8motions.com
>> http://www.opencellid.org
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Openmoko community mailing list
>> community at lists.openmoko.org
>> http://lists.openmoko.org/mailman/listinfo/community
>>
>
> _______________________________________________
> Openmoko community mailing list
> community at lists.openmoko.org
> http://lists.openmoko.org/mailman/listinfo/community
>
--
Thomas LANDSPURG
8Motions
Founder/CTO
http://www.8motions.com
http://www.opencellid.org
More information about the community
mailing list
