Subject: [Geopriv] questions on uncertainty

From: Nick Doty <[email-masked]>
Date: Wed, 6 Nov 2013 22:29:07 -0800

A couple comments from reading documents before tomorrow's meeting:

Re draft-thomson-geopriv-uncertainty-08

> Civic addresses [RFC5139] inherently include uncertainty, based on
>    the area of the most precise element that is specified.

Is that correct? If I'm trying to express a point location, then a civic address will include that area-based level of uncertainty, but is PIDF-LO only used to express points? If I tell you that I live at 123 Main St., there is no uncertainty. (Similarly: "I'm from Oakland.")

>    Note:  The centroid of a concave Polygon or Arc-Band shape is not
>       necessarily within the region of uncertainty.

Indeed! This is one of the reasons that in different use cases, different point conversions might be appropriate. Is there a particular reason for geopriv to precisely document the centroid method when implementers will have their own reasons to use different algorithms?

Looking forward to chatting in person.
—Nick

---

From: James Winterbottom <[email-masked]>
Date: Thu, 7 Nov 2013 17:41:23 +1100

Hi Nick,

123 Mian st may well be a 1/4 acre block. If it is a two story house, are you on the ground floor or the first floor, which room in the house? Answers to these questions reduce the uncertainty. Does that help a bit?

On the second point I will defer to Martin.

Cheers
James

On 7 Nov 2013, at 5:29 pm, Nick Doty <[email-masked]> wrote:

> _______________________________________________
> Geopriv mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/geopriv

---

From: Nick Doty <[email-masked]>
Date: Wed, 6 Nov 2013 22:52:12 -0800

> 123 Mian st may well be a 1/4 acre block. If it is a two story house, are you on the ground floor or the first floor, which room in the house? Answers to these questions reduce the uncertainty. Doe…

Right, if I'm trying to express the precise (point-like) geographic location of a single human body at a single point in time, then a civic address will include some uncertainty, perhaps quite a bit. But what I was trying to illustrate with a couple of English sentences is that civic address descriptors are often used in a coherent way without that point-like quality. "I live at 123 Main St." "I'm from Oakland." Or in the canonical pizza delivery example, it's not uncertainty when I give the shop my street address instead of the part of the house I'm sitting in when I order.

Maybe I'm mistaken that this is relevant to the geopriv use cases, but I at least hope I've explained the point a bit better.

Thanks,
Nick

---

From: James Winterbottom <[email-masked]>
Date: Thu, 7 Nov 2013 18:25:57 +1100

I think you are saying that the degree of precision required relates to the service being requested and if that is the case then I agree with you.

Cheers
James

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Thu, 7 Nov 2013 14:48:33 +0000

Nick,

I agree with you that a civic address in itself doesn¹t have uncertainty,
it describes an area, that it¹s purpose.  When using a civic address to
describe the location of something contained within that area, the
uncertainty isn¹t with the civic address, but where the something is
within the area described.

-Marc-

-----Original Message-----
From: Nick Doty <[email-masked]>
Date: Wednesday, November 6, 2013 at 10:52 PM
To: James Winterbottom <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Subject: Re: [Geopriv] questions on uncertainty

>> 123 Mian st may well be a 1/4 acre block. If it is a two story house,
>>are you on the ground floor or the first floor, which room in the house?
>>Answers to these questions reduce the uncertainty. Does that help a bit?
>
>Right, if I'm trying to express the precise (point-like) geographic
>location of a single human body at a single point in time, then a civic
>address will include some uncertainty, perhaps quite a bit. But what I
>was trying to illustrate with a couple of English sentences is that civic
>address descriptors are often used in a coherent way without that
>point-like quality. "I live at 123 Main St." "I'm from Oakland." Or in
>the canonical pizza delivery example, it's not uncertainty when I give
>the shop my street address instead of the part of the house I'm sitting
>in when I order.
>
>Maybe I'm mistaken that this is relevant to the geopriv use cases, but I
>at least hope I've explained the point a bit better.
>
>Thanks,
>Nick

---

From: "Rosen, Brian" <[email-masked]>
Date: Thu, 7 Nov 2013 17:28:00 +0000

This is the same as with a geo.

124 Main St means you are somewhere within 124 Main, don’t know where.  If I say “Floor 2”, that helps.  If I say “Floor 2, Master Bedroom” that helps more.
Unlike with a  geo, it’s hard to characterize uncertainty with meaningful metrics, but the concepts are the same.

Brian

---

From: Martin Thomson <[email-masked]>
Date: Thu, 7 Nov 2013 09:40:15 -0800

> Is that correct? If I'm trying to express a point location, then a civic address will include that area-based level of uncertainty, but is PIDF-LO only used to express points? If I tell you that I…

Ahh, this statement has caused some confusion in the past,
particularly due to the use of the word uncertainty, which in its
colloquial form has a meaning very different to the precise definition
in the document.

When I say that a Target is within 50 metres of some latitude and
longitude, that statement in and of itself does not bear any
uncertainty in the classic sense.  The classic understanding of
uncertainty - the chance that something might be wrong - is embodied
in the *confidence* value.  By the strictly defined terms of this
draft, the region of uncertainty lies in what has not been specified -
i.e., the region of uncertainty.

The location in the statement "I'm from Oakland" implies uncertainty
about everything other than city.  If I said "I grew up in Camden",
that too describes an area.

The bottom line is that since you are describing an area, you are
doing exactly what we do when we describe regions of uncertainty using
circles or ellipsoids or prisms.  (In my example, and maybe yours,
it's a non-contiguous area, because unless you knew something more
about me, you might have trouble identifying even the country that I'm
talking about.)

> Indeed! This is one of the reasons that in different use cases, different point conversions might be appropriate. Is there a particular reason for geopriv to precisely document the centroid method…

The intent of these sections is to provide a set of the most primitive
tools for those who don't already have a way of dealing with
uncertainty.  This isn't intended to constrain behaviour; if you have
a different use case, then you are able to use different or more
sophisticated point conversions.  I know that when I was working in
cellular location, our conversions from arc band did not use centroid
for a couple of good reasons.

> Looking forward to chatting in person.

Likewise.

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Thu, 7 Nov 2013 18:00:16 +0000

Brian,

I think you missed the point (pun intended).

124 Main St., any town, any state, any country, describes the location of
a area of land as defined by a governmental agency.  What is the
uncertainty associated with where that area of land is located?

Your example is attempting to locate a person within that area of land.
Yes, there is uncertainty associated with where that person might be
within the confines of 124 Main St., but that’s an artifact of using a
location description intended for a area of land to define where a person
is located.

It’s all about the use case.  If you are attempting to deliver a package
addressed to 124 Main St., there is no uncertainty.

-Marc- 

-----Original Message-----
From: <Rosen>, Brian <[email-masked]>
Date: Thursday, November 7, 2013 at 9:28 AM
To: Marc Linsner <[email-masked]>
Cc: Nick Doty <[email-masked]>, "[email-masked]"
<[email-masked]>

>124 Main St means you are somewhere within 124 Main, don’t know where.
>If I say “Floor 2”, that helps.  If I say “Floor 2, Master Bedroom” that
>helps more.

---

From: "Rosen, Brian" <[email-masked]>
Date: Thu, 7 Nov 2013 18:06:20 +0000

If I draw you a square polygon and say deliver the package to that
polygon, I get the same result.

Today, we encode uncertainty of a geo in a polygon.  Today, we encode
uncertainty of a civic with an incomplete set of elements.  Same thing.

The problem with what we are doing today is that we’re not explicit about
uncertainty.

Brian

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Thu, 7 Nov 2013 18:15:40 +0000

This is funny...

If I’m looking for 124 Main St. where is the uncertainty?

From Martin’s draft…

"Uncertainty results from the limitations of measurement.”

124 Main St. is not the result of a measurement. It’s a description

-Marc-

>>>Unlike with a  geo, it’s hard to characterize uncertainty with
>>>meaningful
>>>metrics, but the concepts are the same.
>>>
>>>Brian
>>>
>>>>> Maybe I'm mistaken that this is relevant to the geopriv use cases,
>>>>>but
>>>>>I

---

From: Martin Thomson <[email-masked]>
Date: Thu, 7 Nov 2013 10:22:55 -0800

> 124 Main St. is not the result of a measurement. It’s a description

Ok, sure, it's a quantization or truncation error.

However, this raises a good, clean issue.  The draft doesn't deal with
the fact that some amount of uncertainty arises from the limitations
of the format in which the location is represented.

This is a problem we already have, but haven't been good at
highlighting.  We might know about a 500 point polygon describing an
area, but are forced to make a larger area with fewer points to convey
to others (since we recommend a maximum of 15 points).

Thanks for pointing out the shortcoming in the definition.

---

From: "Rosen, Brian" <[email-masked]>
Date: Thu, 7 Nov 2013 18:29:06 +0000

If I’m looking for 33.1234,108.2276, where is the uncertainty?
33.1234, 108.2276 is not the result of a measurement, it’s an expression
of absolute position on the earth.

Now, if I’m using a GPS to figure out where I am in relation to 33.1234,
108.2276, then I have uncertainty.

If I’m using my eyes to figure out where I am in relation to 124 Main,
then I have uncertainty.

124 Main is not a description, it’s an expression of an absolute position
on the earth (given that we agree on which 124 Main).

If I want you to go to 124 Main St, where do I want you to go?  Front
door, inside, curb?  Lot’s of uncertainty.

Brian
On 11/7/13, 10:15 AM, "Marc Linsner (mlinsner)" <[email-masked]> wrote:

>>>>On Nov 7, 2013, at 6:48 AM, Marc Linsner (mlinsner)
>>>><[email-masked]>
>>>>wrote:
>>>>
>>>>> Nick,
>>>>>

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Thu, 7 Nov 2013 18:43:59 +0000

>door, inside, curb?  Lot¹s of uncertainty.

That¹s orthogonal to the discussion of uncertainty associated with civic
location 124 Main St.

No, you did not measure 124 Main St.

-Marc-

---

From: Martin Thomson <[email-masked]>
Date: Thu, 7 Nov 2013 10:59:27 -0800

> No, you did not measure 124 Main St.

I think we're getting off track.  Does my answer to this question work for you?

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Thu, 7 Nov 2013 19:27:50 +0000

Martin,

I believe the GeoPriv-ites continually work under the assumption of
locating a human.

In the draft you equate uncertainty to the various (missing) elements of a
civic location.  All I’m trying to point out is for use cases other than
locating a human, a missing element of a civic location may not equate to
uncertainty.

If I’m looking to evaluate the purchase of a piece of vacant property
located at 123 Main St, Anytown, AnyState, AnyCountry, there is no
uncertainty as to the location.  The fact the LMK, FLR, UNIT, ROOM, SEAT
are missing doesn’t imply uncertainty.  The use case is fulfilled as soon
as I step foot on the plat of land.

-Marc-

-----Original Message-----
From: Martin Thomson <[email-masked]>
Date: Thursday, November 7, 2013 at 10:59 AM
To: Marc Linsner <[email-masked]>
Cc: "Rosen, Brian" <[email-masked]>, "[email-masked]"
<[email-masked]>

---

From: Martin Thomson <[email-masked]>
Date: Thu, 7 Nov 2013 13:38:05 -0800

Yes, I can understand that you might find this assumption to be a
problem and I recognize that our basic mechanisms are better suited to
point positioning than anything else.  For the purposes of our work,
the distinction isn't really a determining factor most of the time.

I think that we can address that concern by placing this firmly out of
scope for this draft.

---

From: Randall Gellens <[email-masked]>
Date: Thu, 7 Nov 2013 18:05:51 -0800

At 6:00 PM +0000 11/7/13, Marc Linsner (mlinsner) wrote:

>  within the confines of 124 Main St., but that's an artifact of using a
>  It's all about the use case.  If you are attempting to deliver a package

That's because there is out-of-band information available to the 
package delivery person (e.g., knowledge that deliveries go to the 
front door of a residence, loading dock of a business, knowledge of 
how to locate the front door or loading dock).

-- 
Randall Gellens
Opinions are personal;    facts are suspect;    I speak for myself only
-------------- Randomly selected tag: ---------------
The brain is a wonderful organ; it starts working the moment you get
up in the morning, and does not stop until you get to work.
                                                      --Robert Frost

---

From: Roger Marshall <[email-masked]>
Date: Fri, 8 Nov 2013 02:51:52 +0000

Yeah, that's right.  There's no uncertainty that you are at 124 Main Street, but there may be a little uncertainty as to where you set the box down.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Randall Gellens
Sent: Thursday, November 07, 2013 6:06 PM
To: Marc Linsner (mlinsner); Rosen, Brian
Cc: [email-masked]
Subject: Re: [Geopriv] questions on uncertainty

At 6:00 PM +0000 11/7/13, Marc Linsner (mlinsner) wrote:

> location description intended for a area of land to define where a 
> person  is located.
>
>  It's all about the use case.  If you are attempting to deliver a 
> package  addressed to 124 Main St., there is no uncertainty.

That's because there is out-of-band information available to the package delivery person (e.g., knowledge that deliveries go to the front door of a residence, loading dock of a business, knowledge of how to locate the front door or loading dock).

--
Randall Gellens
Opinions are personal;    facts are suspect;    I speak for myself only
-------------- Randomly selected tag: --------------- The brain is a wonderful organ; it starts working the moment you get up in the morning, and does not stop until you get to work.
                                                      --Robert Frost _______________________________________________
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https://www.ietf.org/mailman/listinfo/geopriv

CONFIDENTIALITY NOTICE: The information contained in this message may be privileged and/or confidential. If you are not the intended recipient, or responsible for delivering this message to the intended recipient, any review, forwarding, dissemination, distribution or copying of this communication or any attachment(s) is strictly prohibited. If you have received this message in error, please notify the sender immediately, and delete it and all attachments from your computer and network.

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From: James Winterbottom <[email-masked]>
Date: Fri, 8 Nov 2013 14:23:19 +1100

I think that this is confusing confidence and uncertainty.
You have high confidence that you are at the right address.
The uncertainty is where in the address to put the package.

Cheers
James

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Fri, 8 Nov 2013 06:32:19 +0000

No, this is an application issue, not a location representation issue.

The shipping instructions were ³124 Main St.².  The driver do not have to
guess which residence to stop at, there is no uncertainty where 124 Main
St. is located.

Associating location respresentation uncertainty with the question of
where to place the package within the confines of 124 Main St. is simply
wrong.  If normal convention is to place the package at the front door of
the structure at 124 Main St., so be it, that¹s an application = package
delivery issue.

What are you confusing is the location given for package delivery was not
adequate for the task at hand.  That doesn¹t equate to uncertainty with
the location representation.

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]>
Cc: "[email-masked]" <[email-masked]>, "Rosen,	Brian"
<[email-masked]>, Randall Gellens <[email-masked]>, Marc
Linsner <[email-masked]>
Subject: Re: [Geopriv] questions on uncertainty

>> Yeah, that's right.  There's no uncertainty that you are at 124 Main
>>Street, but there may be a little uncertainty as to where you set the
>>box down.
>> 
>>package delivery person (e.g., knowledge that deliveries go to the front
>>door of a residence, loading dock of a business, knowledge of how to
>>locate the front door or loading dock).
>> 
>> --
>> Randall Gellens
>> -------------- Randomly selected tag: --------------- The brain is a
>>wonderful organ; it starts working the moment you get up in the morning,
>>and does not stop until you get to work.
>>                                                      --Robert Frost
>> CONFIDENTIALITY NOTICE: The information contained in this message may
>>be privileged and/or confidential. If you are not the intended
>>recipient, or responsible for delivering this message to the intended
>>recipient, any review, forwarding, dissemination, distribution or
>>copying of this communication or any attachment(s) is strictly
>>prohibited. If you have received this message in error, please notify
>>the sender immediately, and delete it and all attachments from your
>>computer and network.

---

From: James Winterbottom <[email-masked]>
Date: Fri, 8 Nov 2013 17:59:39 +1100

I respectfully disagree.
You are arguing that because the location provided is sufficiently good for the application or service being requested that there is no uncertainty. I disagree with that. We could, using the right instruments, measure a property boundary to the nearest mm and for anything useful that is way more accurate than is required, but that does not mean that there is no uncertainty.

Cheers
James

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Fri, 8 Nov 2013 13:20:52 +0000

No, I arguing that there is no uncertainty as to where the steel surveyor
stakes are located that outline the polygon represented by 124 Main St.
Those stakes can be located with certainty (at least to satisfaction of a
court of law).

My point all along, and what I believe I said in the meeting, is that
uncertainty associated with geodetic location is applied significantly
different than uncertainty associated with a civic location.  I believe
there is enough difference that discussing them in a single document only
causes confusion for the reader.

Do we truly believe we will see pidf-lo with a civic location and the new
"<con:confidence pdf="normal">67</con:confidence>” field?

I’m suggesting that we leave civic location out of the uncertainty
discussion, or as I suggested in the meeting, write a separate document
explaining it.

Martin promised new text which I look forward to reading.

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]>
Date: Thursday, November 7, 2013 at 10:59 PM
To: Marc Linsner <[email-masked]>
Cc: Roger Marshall <[email-masked]>, Randall Gellens
<[email-masked]>, "[email-masked]" <[email-masked]>
Subject: Re: [Geopriv] questions on uncertainty

>I respectfully disagree.
>You are arguing that because the location provided is sufficiently good
>for the application or service being requested that there is no
>uncertainty. I disagree with that. We could, using the right instruments,
>measure a property boundary to the nearest mm and for anything useful
>that is way more accurate than is required, but that does not mean that
>there is no uncertainty.
>
>Cheers
>James
>
>>>>front

---

From: Robin Wilton <[email-masked]>
Date: Fri, 8 Nov 2013 09:42:21 -0800

My 2c; I agree with Marc's analysis below. Identifying a delivery address and knowing where to put the package are two different problems. 

To make the distinction more evident, imagine that, instead of relying on a human delivery agent, you are having to automate delivery of the parcel by a robot. You can now no longer rely on conventions/implicit assumptions about where a front door might be, where the doorbell is, etc., and your instructions to the robot have to be correspondingly more detailed and explicit.

Robin Wilton
Technical Outreach Director - Identity and Privacy
Internet Society

email: [email-masked]
Phone: +44 705 005 2931
Twitter: @futureidentity

---

From: "Rosen, Brian" <[email-masked]>
Date: Fri, 8 Nov 2013 17:50:05 +0000

Okay, but, remembering that we agreed on a resolution of this issue in the meeting:

We CAN have a notion of uncertainty of a civic location.  It is application dependent.
The uncertainty is similar to the rectangular uncertainty area of a geo measurement.

If I say I am in New York State, United States, I have equal probability of being anywhere in New York State.
If I say I am at 124 Main St, Buffalo, NY, US, I have equal probability of being anywhere in 124 Main St, Buffalo, NY, US
If I say I am on the 2nd floor of 124 Main St, …, I have equal probability of being anywhere on the 2nd floor, …

It’s not really a MEASUREMENT uncertainty though, it’s a lack of specificity in the expression of the location.

Brian

On Nov 8, 2013, at 9:42 AM, Robin Wilton <[email-masked]<mailto:[email-masked]>> wrote:

Robin Wilton

email: [email-masked]<mailto:[email-masked]>
Phone: +44 705 005 2931
Twitter: @futureidentity

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen, Brian"
<[email-masked]<mailto:[email-masked]>>, Randall Gellens <[email-masked]<mailto:[email-masked]>>, Marc
Linsner <[email-masked]<mailto:[email-masked]>>
Subject: Re: [Geopriv] questions on uncertainty

Cheers
James

On 8 Nov 2013, at 1:51 pm, Roger Marshall <[email-masked]<mailto:[email-masked]>>
wrote:

-----Original Message-----
From: [email-masked]<mailto:[email-masked]> [mailto:[email-masked]] On
Behalf Of Randall Gellens
Sent: Thursday, November 07, 2013 6:06 PM
To: Marc Linsner (mlinsner); Rosen, Brian
Cc: [email-masked]<mailto:[email-masked]>
Subject: Re: [Geopriv] questions on uncertainty

[email-masked]<mailto:[email-masked]>

[email-masked]<mailto:[email-masked]>

_______________________________________________
Geopriv mailing list
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From: Martin Thomson <[email-masked]>
Date: Fri, 8 Nov 2013 09:53:07 -0800

I'm afraid that this is exactly the case I was talking about in the
session.  PIDF-LO creates a binding between a thing and its location.
That binding is where the uncertainty lies.

If the intent is to identify a location, that is a separate issue.

On 8 November 2013 09:42, Robin Wilton <[email-masked]> wrote:
> My 2c; I agree with Marc's analysis below. Identifying a delivery address
> and knowing where to put the package are two different problems.
>
> To make the distinction more evident, imagine that, instead of relying on a
> human delivery agent, you are having to automate delivery of the parcel by a
> robot. You can now no longer rely on conventions/implicit assumptions about
> where a front door might be, where the doorbell is, etc., and your
> instructions to the robot have to be correspondingly more detailed and
> explicit.
>
> Robin Wilton
> On 8 Nov 2013, at 1:51 pm, Roger Marshall <[email-masked]>
>
> wrote:
>
>
> From: [email-masked] [mailto:[email-masked]] On
>

---

From: Martin Thomson <[email-masked]>
Date: Fri, 8 Nov 2013 09:54:55 -0800

On 8 November 2013 09:50, Rosen, Brian <[email-masked]> wrote:
> If I say I am at 124 Main St, Buffalo, NY, US, I have equal probability of
> being anywhere in 124 Main St, Buffalo, NY, US

Thanks Brian, that is correct.  Though we need to qualify with  "...a
lack of specificity in the expression of the location for the purposes
of describing the location of a Target."

---

From: James Winterbottom <[email-masked]>
Date: Sat, 9 Nov 2013 06:12:21 +1100

Well said Brian.

Sent from my iPad

On 09/11/2013, at 4:50 AM, "Rosen, Brian" <[email-masked]> wrote:

> On Nov 8, 2013, at 9:42 AM, Robin Wilton <[email-masked]> wrote:
>

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Fri, 8 Nov 2013 20:25:16 +0000

What confidence value will you express for each example??

-Marc-

On Nov 8, 2013, at 11:50 AM, "Rosen, Brian" <[email-masked]<mailto:[email-masked]>> wrote:

Brian

Robin Wilton

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen, Brian"

Cheers
James

---

From: "Rosen, Brian" <[email-masked]>
Date: Fri, 8 Nov 2013 20:28:11 +0000

Since these are not measurements, in many cases, confidence approaches 100%.  There are probably circumstances where it isn’t.

Brian

On Nov 8, 2013, at 12:25 PM, Marc Linsner (mlinsner) <[email-masked]<mailto:[email-masked]>> wrote:

-Marc-

Brian

Robin Wilton

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen, Brian"

Cheers
James

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Fri, 8 Nov 2013 20:38:24 +0000

So you are stating that expressing a civic location that lacks the specificity to carry out the intended application is called location uncertainty (roughly equivalent to measurement uncertainty)??

-Marc-

On Nov 8, 2013, at 2:28 PM, "Rosen, Brian" <[email-masked]<mailto:[email-masked]>> wrote:

Brian

-Marc-

Brian

Robin Wilton

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen, Brian"

Cheers
James

---

From: "Rosen, Brian" <[email-masked]>
Date: Fri, 8 Nov 2013 20:46:41 +0000

I didn’t say that, and I don’t mean that.

It may be perfectly acceptable to know that I am equally likely to be anywhere in Buffalo, NY,US, and It may not be acceptable.  But reporting my location as Buffalo, NY, US is reporting my location as somewhere in the city, with uncertainty as to where in the city I am.  Whether that is lacking in specificity is application dependent and out of scope for geopriv.

Brian

From: Marc Linsner <[email-masked]<mailto:[email-masked]>>
Date: Friday, November 8, 2013 at 4:38 PM
To: Brian Rosen <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>
Subject: Re: [Geopriv] questions on uncertainty

-Marc-

Brian

-Marc-

Brian

Robin Wilton

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen,Brian"

Cheers
James

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Fri, 8 Nov 2013 21:10:39 +0000

So this circular discussion is almost full circle.

We know for certain where to look for Buffalo, NY, US.

You believe that the IETF should make users of pidf-lo aware that even though the stated civic location representation is fit for the application at hand, there is uncertainty associated with the location representation.

What you are stating is that a civic location may lack the elements required to carry-out the application.  I agree, that's not a GeoPriv issue.  So, if the lack of such elements is what causes the uncertainty, why are we talking about it?

-Marc-

On Nov 8, 2013, at 2:46 PM, "Rosen, Brian" <[email-masked]<mailto:[email-masked]>> wrote:

Brian

-Marc-

Brian

-Marc-

Brian

Robin Wilton

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen,Brian"

Cheers
James

---

From: "Rosen, Brian" <[email-masked]>
Date: Fri, 8 Nov 2013 21:15:05 +0000

The uncertainty draft has a section on civic.  Perhaps this discussion will result in some edits to that section, providing a clearer explanation of what kind of uncertainty you might have in a civic.  That section does’t suggest any action, it just makes some observations.  That’s fine with me.

Brian
On Nov 8, 2013, at 1:10 PM, Marc Linsner (mlinsner) <[email-masked]<mailto:[email-masked]>> wrote:

-Marc-

Brian

-Marc-

Brian

-Marc-

Brian

Robin Wilton

-Marc-

-----Original Message-----
From: James Winterbottom <[email-masked]<mailto:[email-masked]>>
Date: Thursday, November 7, 2013 at 7:23 PM
To: Roger Marshall <[email-masked]<mailto:[email-masked]>>
Cc: "[email-masked]<mailto:[email-masked]>" <[email-masked]<mailto:[email-masked]>>, "Rosen,Brian"

Cheers
James

---

From: Martin Thomson <[email-masked]>
Date: Fri, 8 Nov 2013 21:29:30 -0800

> We know for certain where to look for Buffalo, NY, US.

The uncertainty exists in whether the subject of the PIDF-LO is in Buffalo.

There is probably a level of confidence that this is correct, which
may vary depending on who is consuming the PIDF-LO, though the
expression of confidence is made by the Location Generator.

However, if we are talking specifically about Buffalo, then that's
different, and not really something that PIDF-LO is good for (though
the civic address format might still be a good way to talk about
that).  That is, unless the presentity itself is Buffalo and then
there is little point in the PIDF-LO encapsulation.

---

From: "Marc Linsner (mlinsner)" <[email-masked]>
Date: Mon, 11 Nov 2013 14:34:39 +0000

>The uncertainty exists in whether the subject of the PIDF-LO is in

Understood and agree, that¹s why we have 35+ elements for civic location
(including the catch-all ŒLOC').  And, as you state in section 3.2 the of
draft, missing elements are the cause of uncertainty.  Of course, which
elements are necessary is completely application dependent.

IMHO, it¹s not for the IETF to tell readers that if they don¹t send all
the civic location elements required by the application, there will be
uncertainty.  We (used to) teach children at a very young age how to
address an envelope, I don¹t see the point in the IETF having to do that
again.

I do think the draft is great at explaining uncertainty derived from
location measurement.  It¹s a necessary primer for the follow-on Œconf¹
draft.  But, I believe, there is enough departure between the meaning of
uncertainty from location measurement and uncertainty due to lack of civic
elements that the 2 should not be discussed in the same draft.  I really
don¹t think the IETF needs to discuss uncertainty with civic location at
all.

-Marc-