Re: [Geopriv] Some comments on draft-thomson-geopriv-uncertainty-08

[James Winterbottom <[e-mail]>]

Sure you can.
We have an explicit radius parameter for circle, you may set this to zero.
We also allow,the definition of just a point.
I think that you will find that the constructs between MLP and GeoShape are almost directly interchangeable.

Cheers
James

Sent from my iPad

On 09/11/2013, at 4:33 AM, Brian Rosen <[e-mail]> wrote:

> Not claiming I know more than you, but I think E2 and MLP report position AND they report uncertainty by describing the position as a point, and the uncertainty as the radius of a circle or ellipse.  They don’t just sent a circle.  It’s point plus circular uncertainty, not just a circle.  In PIDF, you can’t tell the difference between a location reported as a circle with no uncertainty specified from a point with circular uncertainty.
> 
> The definition of the reported position is the lat/lon of the position and the radius of uncertainty.  We have no similar way to report uncertainty in PIDF.
> 
> Brian
> 
> On Nov 7, 2013, at 2:00 PM, James Winterbottom <[e-mail]> wrote:
> 
>> Hi Brian,
>> 
>> MLP and E2 are essentially the same as what we use in Geopriv
>> 
>> Sent from my iPad
>> 
>> On 08/11/2013, at 8:49 AM, Brian Rosen <[e-mail]> wrote:
>> 
>>> Sure:
>>> 
>>> When you get a location from a GPS receiver, it typically uses the NMEA interface, which reports a lat/lon and a Dilution of Precision method of specifying uncertainty.
>>> MLP usually reports location as point with circle, ellipse or arc uncertainty
>>> E2 usually reports location as point with uncertainty
>>> 
>>> Brian
>>> 
>>> On Nov 7, 2013, at 1:02 PM, James Winterbottom <[e-mail]> wrote:
>>> 
>>>> Hi Brian,
>>>> 
>>>> Can you give an example of point 2 please?
>>>> I guess all the systems that I am familiar with use the area to express the uncertainty so I am keen to understand how it might be done differently.
>>>> 
>>>> Cheers
>>>> James
>>>> 
>>>> Sent from my iPad
>>>> 
>>>> On 08/11/2013, at 7:48 AM, Brian Rosen <[e-mail]> wrote:
>>>> 
>>>>> I’ve read this draft, and think it is an excellent explanation of the issues we face in geopriv with measurements.  I highly recommend that we adopt the draft and process it as a work group item.  I am particularly happy with the definitions it offers for the various quantities.
>>>>> 
>>>>> 
>>>>> 
>>>>> I find it lacking in two areas:
>>>>> 
>>>>> 
>>>>> 
>>>>> 1. I think the draft needs to discuss the issues of comparing measurements with different confidence.  I think the bottom line on that is: don’t do it, use one agreed upon confidence.
>>>>> 
>>>>> 2. I think we need to stop expressing measurements as just the uncertainty area.  While I understand why doing so is attractive, I think it is not what real systems do.  Real systems express a measurement and explicitly state the uncertainty of the measurement.  I think we need a way to express that.
>>>>> 
>>>>> 
>>>>> 
>>>>> Brian
>>>>> 
>>>>> _______________________________________________
>>>>> Geopriv mailing list
>>>>> [e-mail]
>>>>> https://www.ietf.org/mailman/listinfo/geopriv
>>> 
>