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

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 <a.james.winterbottom@gmail.com> 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 <br@brianrosen.net> 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
>> 
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