Subject: Confidence (was: Geopriv WG - meeting 5-6 Jun, other news)

From: "Zmolek, Andrew (Andrew)" <[email-masked]>
Date: Fri, 17 May 2002 11:23:30 -0600

Richard Shockey wrote:

> I have to admit that I am struggling with how to 
> express the concept of confidence in the accuracy 
> of the location data source.. 
> if you look at the problem set in wireless it might 
> help in determine what may or may not be needed here 

Wireless confidence is very focused on measurement, but let's keep in mind that confidence might also be expressible in terms of intelligence that can infer location indirectly (i.e. based on what I know I'm 70% sure you are in your office right now). If this intelligence wasn't derived by signal triangulation or GPS, than confidence measurement is a bit more subjective.

--Andy Zmolek 
    Technology & Standards Engineer 
      CTO Standards 
        Avaya Inc. 

            [email-masked] 
              +1 720 444 4001 
                sip:[email-masked]

---

From: Dan Greening <[email-masked]>
Date: Sat, 18 May 2002 10:01:48 -0700

In the LIF variant, confidence (although I'm not sure that's the right
word here) is expressed as a shape.

You can see examples of this in the LIF (Location Interoperability
Forum) Mobile Location Protocol specification (technically "LIF TS 101
v2.0.0").  I hope you IETF folks are referring to that, we spent a lot
of time getting it right (especially in the public-within-weeks LIF TS
101 v3.0.0, which incorporates shapes and coordinate reference systems
from OGC's GML (Geographic Markup Language).

In particular, some typical regions are 

. A circle or ellipse (if you are doing cell-id with a tower with a
non-directional antenna, or GPS).
. A cone (if you are doing cell-id with a directional antenna on a
tower)
. A "banana" (if you are doing cell-id with a directional antenna on a
tower, and you are using timing-advance)

You get some really funky regions if you have detailed coverage
information and you are in a mountainous region.  A set of disjoint
mountaintops, for example.

Dan Greening, Ph.D.  CEO, BigTribe Corporation 
              330 Townsend Street, Suite 209, San Francisco, CA
94107-1662 
              [email-masked]  +1(415)995-7151  fax 995-7155

-----Original Message-----
From: Zmolek, Andrew (Andrew) [mailto:[email-masked]] 
Sent: Friday, May 17, 2002 10:24 AM
To: Richard Shockey; James M. Polk; Allison Mankin;
[email-masked]
Cc: [email-masked]; [email-masked]
Subject: Confidence (was: Geopriv WG - meeting 5-6 Jun, other news)

> help in determine what may or may not be needed here 

Wireless confidence is very focused on measurement, but let's keep in
mind that confidence might also be expressible in terms of intelligence
that can infer location indirectly (i.e. based on what I know I'm 70%
sure you are in your office right now). If this intelligence wasn't
derived by signal triangulation or GPS, than confidence measurement is a
bit more subjective.

--Andy Zmolek 

            [email-masked] 
              +1 720 444 4001 
                sip:[email-masked]

---

From: Richard Shockey <[email-masked]>
Date: Sat, 18 May 2002 15:37:27 -0400

>word here) is expressed as a shape.

humm.

>from OGC's GML (Geographic Markup Language).

IYHO how much of GML could/should  be adapted to the task a hand .. do you 
have any URL's to documents that describe this in more detail ..

thank you ..

Richard Shockey, Senior Manager, Strategic Technology Initiatives
NeuStar Inc.
45980 Center Oak Plaza   Bldg 8     Sterling, VA  20166
1120 Vermont Ave NW Suite 400 Washington DC 20005
Voice +1 571.434.5651 Cell : +1 314.503.0640,  Fax: +1 815.333.1237
<mailto: [email-masked]> or
<mailto: [email-masked]>
<http://www.neustar.biz>
<http://www.enum.org>
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

---

From: Dan Greening <[email-masked]>
Date: Sat, 18 May 2002 12:58:56 -0700

The MLP 2.0.0 spec is
http://www.locationforum.org/publicdownload/LIF-TS-101-v2.0.0.zip.
There are a lot of fixes in 3.0.0, and 2.0.0 doesn't contain the OGC
style shapes or OGC CoordinateReference system specification (we did our
own, which we later regretted). 

If you're a member of LIF or OGC you can get the 3.0.0 draft now, but
otherwise have to wait a couple of weeks.  It might be out just before
the Geopriv meeting.

The only things coming from GML are shapes, and in fact only a few of
them would typically be used for this particular purpose.  GML is at
http://www.opengis.net/gml/02-009/GML2-11.html.  Shapes are all
specializations of Geometry.

-----Original Message-----
From: Richard Shockey [mailto:[email-masked]] 
Sent: Saturday, May 18, 2002 12:37 PM
To: Dan Greening; [email-masked]
Subject: RE: Confidence (was: Geopriv WG - meeting 5-6 Jun, other news)

humm.

>from OGC's GML (Geographic Markup Language).

IYHO how much of GML could/should  be adapted to the task a hand .. do
you 
have any URL's to documents that describe this in more detail ..

thank you ..

---

From: "James M. Polk" <[email-masked]>
Date: Tue, 21 May 2002 19:19:31 -0500

At 11:23 AM 5/17/2002 -0600, Zmolek, Andrew (Andrew) wrote:
>Richard Shockey wrote:
>....<snip>....but let's keep in mind 
>that confidence might also be expressible in terms of intelligence that can 
>infer location indirectly (i.e. based on what I know I'm 70% sure you are in 
>your office right now). 

I'm troubled by this reasoning or direction the meaning is (might) take --
as I can foresee this confidence percentage directly and
non-deterministically affecting the accuracy value when also present.

Accuracy is a purposeful fudging of the exact location.

Confidence is the best guess with a percentage of where a Location Target is.

If both are present in the reply, then the requestee gets to graph a curve
of if they believe the answer was (close to being) right or not.

Conceivably, I can see the actual location being an order of magnitude from
the location object delivered -- and then what's the point of this
exercise? Plus, the accuracy value known to the Rule Maker isn't even
correct in fudging the location delivered....

>If this intelligence wasn't derived by signal 
>triangulation or GPS, than confidence measurement is a bit more subjective.
>
>--Andy Zmolek 

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