How to assign dimensions to relative positions/ to distances in space-time and other relations between observable entities

In the 53rd CIDOC CRM & 46th FRBRoo SIG meeting, MD presented his HW. 

An effort to theorize about dimensions of spatiotemporal distances, understood as distances btw instances of S15 Observable Entity observed through an Observable Situation (the relation can be seen as one of parthood).

What can be observed is: (a) static properties of a Physical Thing or Material Substantial and events; (b) spatiotemporally bounded situations involving observable entities (locations of things present in events during the time of observation); (c) dynamic processes and sub-situations within them.

The parthood can be expressed through P12 occurred in the presence of, the E93 Presence construct (and properties), location etc.

Observable Situation may be described by a Proposition Set, but restrictions need be implemented. 

Esp. for observable situations in the future: future constraints can be cast in terms of describing an observable situation as a proposition set, which means that the situation materializes when the condition expressed by the proposition set is met/satisfied.

Proposal:

1. parthood of physical things involved in an observation is expressed through: P12 occurred in the presence of, the E93 Presence construct (and properties: P164, P167, P195), location etc.
2. introduction of Sxxy Spatial Distance (IsA Sxxx Observable Situation): Properties
   
   1. Oxxx is distance between: S15 Observable Entity (cardinality constraint: a relation between at least two instances of S15)
   2. Oxxx has dimension: E54 Dimension
3. Observable Situation generalizes over Observations made for a single property. A stepping-stone towards measuring positions and issue 388.
4. Continue the HW of identifying properties that are relevant for Observable Situation

Decision: 

• Start a new issue re specifying possible observable situations in the future
• Continue in this line of work 

Post by Martin Doerr (13 July 2022)

Dear All,

I just saw that I have implicitly proposed a solution to Issue 583 in my homework for Issue 388, as posted today:

What needs now to be spelled out is the direct measurement of distances, angles and differences of dimensions of things, such as weights on a balance.

I propose a "Sxx2 Relative Dimension", IsA E54 Dimension,

 With property:

     Oxx6 is relative to: S15 Observable Entity,  subproperty of O12i has dimension (is dimension of),

 Quantification (2:2,0:n).

 That will not cover angles, because we need 3 reference points. Actually, one is the position of the instrument.

If we allow Oxx6 to be more general in quantification, a further specialization would allow for defining

Sxx3 Angle, IsA Sxx2 Relative Dimension

  and Oxx7 has vertex: S15 Observable Entity, subproperty of Oxx6 is relative to
 Then, we can define how the auxiliary measurements are combined into a position measurement.

Such a "relative dimension" may correspond to an Observable Situation, if measured in the presence of the related entities.

A "Sxx2 Relative Dimension" with P2 has type "spatial distance" corresponds to a spatial relation between the respective related entities.  To be analyzed what that means if events are involved that happened at different times. It would require a memory of the places where they happened. Otherwise, it would be computational via coordinates.

I assume that whatever is indeed measured, requires a sort of simultaneity, except for carrying a clock from one event to another, which again may be a form of simultaneity.

All the best,

Martin
 

In the 54th CIDOC CRM & 47th FRBR/LRMoo SIG meeting, the SIG discussed the proposal by Martin to introduce two new classes in CRMsci, namely: 

• Sxx2 Relative Dimension (isA E54 Dimension), and corresponding property 
  • Oxx6 is relative to: S15 Observable Entity (2:2,0:n) IsA O12i has dimension of (is dimension of), plus
• Sxx3 Angle (isA Relative Dimension), and corresponding property
  • Oxx7 has vertex: S15 Observable Entity, IsA Oxx6 is relative to

Discussion points: 
Similar situation in Linked Conservation Data project: the solution they went for was extremely elaborate and involved defining a reference system through CRMgeo and then approximating the locations of each object. This solution simpler, hence preferable. 
Defining proposed classes/properties logically precedes defining how auxiliary measurements are combined into a Position Measurement 

Decision: Assign HW to draft scope notes for proposed classes and properties. 
HW: MD, GH, MA, DF (& TV to review)

Rome, September 2022
 

In the 56th joint meeting of the CIDOC CRM and ISO/TC46/SC4/WG9 &49th FRBR/LRMoo SIG, the SIG reviewed the proposal by MD to introduce two new classes and a property connecting each one of them to S15 Observable entity, in CRMsci v2.1 and agreed to it. 

Decisions: 

• Introduce Sxx2 Relative Dimension and corresponding property Oxx6 is relative to (has relative dimension) in CRMsci v2.1
  • HW: MD & CEO - Properly define the property quantifier used for Oxx6 is relative to in CRMsci and CRMbase -"many to many, necessary, two (2,n:0,n)”.  
• Introduce Sxx3 Angle and corresponding property Oxx7 has vertex (is vertex of) in CRMsci v2.1. 
  • HW: MD & AG - formulate the missing examples for Sxx3 & Oxx7 and provide citations for them (proposal: to make use of the calculations used by Aristarchusof Samos to infer the distance of the Sun and Moon from the Earth &  measure their circumference)
• HW: AK & TV to take care of assigning said classes/properties numbers in the new release

For the details of the decisions and discussion points made, see the attached document.
Crete, May 2023.