Re: [netmod] Benjamin Kaduk's Discuss on draft-ietf-netmod-geo-location-08: (with DISCUSS and COMMENT)

[Christian Hopps <[e-mail]>]

> On Jul 17, 2021, at 7:24 PM, Benjamin Kaduk <[e-mail]> wrote:
> 
> On Sat, Jul 17, 2021 at 07:17:09PM -0400, Christian Hopps wrote:
>> 
>> 
>>> On Jul 17, 2021, at 6:14 PM, Benjamin Kaduk <[e-mail]> wrote:
>>> 
>>> So, when we refine the coord-accuracy and height-accuracy for an
>>> instantiation of the grouping, what does that mean?
>> 
>> It’s supposed to mean the accuracy of the measurement that is recorded in the grouping. So if the coord-accuracy is .1 and the measurement is lat/long then the accuracy is within 1/10 of a decimal degree. if the measurement is in cart coordinates the accuracy would be 100cm. I don’t think we need to make this anymore complex than that. Is there some text you would like to see to make that clearer?
> 
> The accuracy of the measurement with respect to what?  The coordinate
> system, or the actual physical object?

I really don’t see how this could be so confusing.

This grouping is a location, the accuracy applies to the contained location data. Consider asking this question about some other field like the lat/long — it doesn’t make sense.

I can’t say for sure, but I think you’ve discarded the obvious here and are getting pedantic about something that’s not actually confusing.

Finally, as we (the IETF) are not geo location experts, we had this grouping reviewed by actual industry experts (thanked in the acknowledgment section) and they had no issue with these fields. I would be very hesitant to change what they reviewed as correct at this point based on pedantic musings.

Thanks,
Chris.

> 
> And, if the concept here is that "I made a measurement, and my measurement
> device reported a value to 1/10 of a decimal degree", that would typically
> correspond to a "precision" rather than an "accuracy"
> (https://en.wikipedia.org/wiki/Accuracy_and_precision).
> 
> In either case, I think that "accuracy of the measurement recorded in the
> grouping" is a qualitatively different concept of "accuracy" than the
> listed accuracy of the geodetic-datum, which (AIUI) relates to the maximum
> deviation between the model of the object used by the coordinate system and
> the actual physical object.  So it's not really clear that we should be
> talking the one "overriding" the other.
> 
> -Ben
>