Am 19.04.2014 18:05, schrieb Hanno Schlichting:
On 18.04.2014, at 03:54 , Kevin Everets <[email protected]> wrote:
I'd like to see a visual comparison between recorded and observed Cell
tower info. It may also help to gauge accuracy in a convenient format.
We’ve recently wrote down our next plans in the form of a roadmap at
https://wiki.mozilla.org/CloudServices/Location/Roadmap. Currently we put
“release cell data” as a goal for the second quarter. This would include both a
data dump of the aggregated cell locations (csv, maybe geojson) and sometime
later a map visualization of those cells. We are currently investigating any
legal problems and considering a license for this data. Our preferred license
is currently to put this data into the public domain, maybe via a CC-0 to
clarify what we understand under public domain.
As an example the aggregated cell data looks something like this (lat/lon
shortened a bit for this illustration):
lat | lon | radio | mcc | mnc | lac | cid | psc | range
37.93 | 23.64 | gsm | 202 | 1 | 9 | 5273 | NULL | 2688
We estimate the lat/lon as the average over all observations. And the range as
half the size of a bounding box around all observations. This estimation isn’t
great. But it’s a good enough approach for many use-cases. And in many cases we
only have one to 10 observations to work with per cell, which limits the
algorithms you can use quite a bit.
One thing to note here is that we work with logical cells and not cell towers.
For example in UMTS networks, we most likely have three cells around a tower.
An example illustration is this:
https://developer.att.com/home/support/faqs/lbsfaqs/lbs_basicCellID.gif. As a
result it’s actually more useful to return the center of the cell, as it’s more
likely a person is somewhere in the area, than it is for the person to be right
next to the tower.
Since we only know and care about logical cells at this point, comparisons to
tower locations or tower databases are a bit hard.
How much effort would be required to add pins for cell towers (which is
generally public info) on the map?
Note the above. It’s not that much work and we are planning to get to it in the
next weeks. Our plan is to first release the data in csv form, which will allow
anyone to draw maps with it. And than a bit later figure out how to best
integrate a map into our own website.
Hanno
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@Hanno Schlichting
I guess you've missunderstood my concept/idea in some ways
I know that we don't have that much data about every cell and that we
only save logical cells right now.
But my idea was to make a different database containing the exact
location of cell towers (not logical cells!): lat/lon and the adress and
pictures of the tower and their type (GSM/UMTS/etc.) and which logical
cells belong to them + their direction maybe.
This data would be verified in a certain way. Only verified
members/users can upload data. And we could include existing databases
of towers.
Later on we will be able to use this data to validate data which is
submitted to Ichnaea to prevent brute-forcing or false data.
This second table would bring more consistency into Ichnaea by
preventing it from being compromised by faked data.
The validated users would "protect" existing data by guaranteeing that
it is correct.
They would need to confirm certain changes in their area as well:
Mozstumbler doesn't recognize a certain logical cell anymore in a
certain region and uploads the data but there is a new cell.
Reason: the provider upgraded the cell or replaced it (for example a new
LTE tower).
The user is informed by Ichnaea by email/website/app to check it and
update the information (new address maybe, order deletion of old tower,
this is proved by a GPS and cell scan at the towers location).
One of the mods has to approve the change then.
After that Ichnaea updates its data: the old tower gets deleted from the
database and the new one will be added by users if they scan the area.
This way the database will be more up to date and won't contain too much
towers that don't exist any longer.
And we can filter out wrong data as well.
One question remains:
Would the deletion of towers from the Ichnaea database influence the
statistics on our web-page?
We could also keep the towers and mark them as deprecated and ignore
them when searching for a location but I don't see much sense in keeping
this data since it only takes up (valuable?) storage.
Felix
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