[Crm-sig] NEW ISSUE: Approximate Dimensions

Martin Doerr martin at ics.forth.gr
Wed Oct 16 18:11:46 EEST 2019

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 

A fine example of measurement tolerances is the recent problem of 
determining the proton radius:
See also:

I think it is a question of guide lines how to interpret the absence of 




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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> Crm-sig at ics.forth.gr
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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
  Email: martin at ics.forth.gr
  Web-site: http://www.ics.forth.gr/isl

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