Hi Robert,
I have been a bit sloppy, as always;-).
A phenomenal place is thought to be recognizable within some fuzzy
limits. So, indeed, all spatial coordinates for a phenomenal place are
approximations. For those approximations, we normally use the properties
"has former or current location" or "falls within", which both include
the true place. That means, that the intersection of all those is still
includes the true place. With these properties, I can query absolutely
where the place is guaranteed not to be, and within which limits I find
it. With P189, we mean an approximation of unknown guaranteed relations
to the approximated. So, we cannot query yes or no where the real place
is in relation to the approximation.
The same reasoning holds for many dimensions, but there is no typical
practice as vague as that of providing a point near a place.
On the other side, many dimensions are not stable over time. For those,
each measurement provides another dimension. Many measurements are given
with statistical deviation values. The scenario intersecting all
measurements to get closer to the real value normally does not hold. It
will be a combination of measurement deviations and varying "real
value", and intrinsic fuzziness of the property measured.
Therefore I suggest to regard any dimension as an approximation, except
for counting stable aggregates of things.
Would that make sense:-)?
Best,
Martin
On 10/16/2019 6:54 PM, Robert Sanderson wrote:
Thanks Martin! A couple of clarifying questions, please …
> The point is, that true numerical values of Dimensions do not exist
for continuous value spaces.
Could you explain how you see this being different for E53 Place? The
true Place also doesn’t exist as space is also continuous. Doubly so
as the definition of place says it is independent of matter. No matter
how precise I am about a lat/long/altitude, I still could be more
precise. Or more precise about a location relative to an object as a
frame of reference; notably as this frame of reference would need to
be measured … which would mean that Place would rely on the
Dimensions. So it seems like we can reduce the Place approximation to
a Dimension approximation, at least in the case of relative coordinate
spaces.
> For any approximation with known inclusion or overlap properties to
the real place, P189 should NOT be used. A "real place" can be
confirmed by multiple observations for things that do not move or have
not moved.
And also for this … how would we have multiple observations of the
Place, such that it was clear that they were all approximations of a
single phenomenal place, without using P189? For example, I have a
bounding box for my city of birth, and a centroid pin for it … I
wasn’t born in two places, yet without using P189, I would need to
have two P7s … no? What am I missing? 😊
Many thanks,
Rob
*From: *Crm-sig <[email protected]> on behalf of Martin
Doerr <[email protected]>
*Date: *Wednesday, October 16, 2019 at 8:18 AM
*To: *"[email protected]" <[email protected]>
*Subject: *Re: [Crm-sig] NEW ISSUE: Approximate Dimensions
Dear Robert, All,
Your proposal well taken, but the recent change in the scope note was
exactly that "The properties of the class E54 Dimension allow for
expressing the numerical approximation of the values of instances of
E54 Dimension. ".
The point is, that true numerical values of Dimensions do not exist
for continuous value spaces. Therefore, any measurement and opinion
about the values are approximations.So, there is no need for another
property. Measurements have typically known tolerances, which may be
statistical, as mean deviations, or absolute.
The property P189 was introduced because of the huge number of
geo-referenced resource with no indication how distant or different
the approximating area is from the real place. For any approximation
with known inclusion or overlap properties to the real place, P189
should NOT be used. A "real place" can be confirmed by multiple
observations for things that do not move or have not moved.
This scenario does not exist in the same way for dimensions *in general.*
I recommend to adjust scope notes and guidelines adequately. If a
dimension is given as 10cm, it is per definitionem an approximation,
because no natural thing has dimension
10,00000000000000000000000000000000000000000000000000000000000000000000000
cm.
A fine example of measurement tolerances is the recent problem of
determining the proton radius:
https://en.wikipedia.org/wiki/Proton_radius_puzzle
See also:
http://pdg.lbl.gov/2012/reviews/rpp2012-rev-history-plots.pdf
https://www.quantamagazine.org/proton-radius-puzzle-deepens-with-new-measurement-20160811/
I think it is a question of guide lines how to interpret the absence
of P10a,b.
Opinions?
Best,
Martin
On 10/15/2019 7:13 PM, Robert Sanderson wrote:
Dear all,
In recent history, we have added P189 approximates for the
practically ubiquitous scenario where we have recorded the
approximate “declarative” place of an event, but not the exact
“phenomenal” place. P189 allows us to say that the event took
place at the phenomenal place, which is then approximated by the
declarative place.
Thus:
Birth_of_Rob a E67_Birth ;
p7_took_place_at [
a E53_Place ;
rdfs:label “The exact place Rob was born” ;
p189i_approximated_by [
a E53_Place ;
rdfs:label “New Zealand” ;
// …
]
]
This gives us two significant advantages:
1. We can have multiple declarative places associated with the
single phenomenal place. This allows us to be clear that the
event took place in one location, but we have multiple ways to
describe that location in our information system.
2. If we can be precise (enough) about the phenomenal place (e.g.
we have the GPS coordinates from the digital camera that took
the photograph), then we do not have a different model … we
can simply ascribe those coordinate values to the phenomenal
place.
While the E53 Place scope notes do not talk about approximation,
there is another class that does … the very next one, E54 Dimension.
An instance of E54 Dimension represents the true quantity,
independent from its numerical
approximation, e.g. in inches or in cm.
However, there isn’t a property that allows us to use this same
approximation pattern for Dimensions.
The same advantages would apply:
1. We can have multiple declarative dimensions (10 inches, 25
centimeters) that approximate the true dimension, rather than
implying there are two different dimensions.
2. If we do not have this case, because the dimension is measured
very accurately and has only a single numerical
representation, then we can simply use a single Dimension.
This is also useful for conservation when the same dimension is
measured to different degrees of accuracy with different
instruments or techniques … there is only a single height (for
example) but it is measured with a laser, or by estimation.
Thus I would like to propose the addition of a new property,
Pxxx_approximates_dimension, that mirrors P189_approximates, that
would be used to associate true dimensions with their approximations.
It would be used in exactly the same way as P189:
painting a Human-Made_Object ;
has_dimension [
a Dimension ;
p2_has_type <aat:height> ;
pxxxi_dimension_approximated_by [
a Dimension ;
p90_has_value 10 ;
p91_has_unit <aat:inches>
]
]
Thank you for your consideration of this issue! I’m happy to
write up a draft scope note for discussion if the general issue is
considered to be worthy of inclusion.
Rob
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Dr. Martin Doerr
Honorary Head of the
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Information Systems Laboratory
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
N.Plastira 100, Vassilika Vouton,
GR70013 Heraklion,Crete,Greece
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--
------------------------------------
Dr. Martin Doerr
Honorary Head of the
Center for Cultural Informatics
Information Systems Laboratory
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
N.Plastira 100, Vassilika Vouton,
GR70013 Heraklion,Crete,Greece
Vox:+30(2810)391625
Email: [email protected]
Web-site: http://www.ics.forth.gr/isl
