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

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 <br@brianrosen.net> 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 <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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> 