Issue 225: how to model subfeatures
Posted by Wolfgang Schmidle 13/02/2013
Dear all,
This question has probably been asked before, but I couldn't find an answer: How to model subfeatures?
In Arachne there are many data fields that describe parts of a statue. In general we do not attempt to group these data fields, but probably it makes sense to group together at least the data fields that describe the head or parts of the head. Currently we use P46 E22 for all parts of a statue. For example, "Haarfrisur" ("hairstyle") is modelled as
E22 Man-Made Object (statue)
P46 is composed of E22 Man-Made Object (head)
P46 is composed of E22 Man-Made Object (hairstyle)
P62 depicts E90 Symbolic Object
P2 has type E55 Type (content of "Haarfrisur", for example "einzelne Strhnen").
However, according to the scope note for E26 Physical Feature the head of a contiguous marble statue should actually be modelled as a feature of the statue, i.e. "(statue) P56 bears feature E25 Man-Made Feature (head)" rather than P46 E22, because one cannot determine a natural border between the head and the rest of the statue. By the same logic, the hairstyle is a feature of the head.
But E26 cannot have subfeatures, i.e. we cannot say "E22 (statue) P56 E25 (head) P56 E25 (hairstyle). Technically E25 (head) P46 E22 (hairstyle) would be possible, but that doesn't seem to be the right solution. What would be the correct way of doing it?
(Our current modelling avoids this problem, and since P56 is a subproperty of P46 I guess it is good enough, even though it could be more precise. Would you agree?)
Posted by Martin 13/02/2013
Dear Wolfgang, thank you for that!
The interesting thing is, that features are bound to a specific object, be it our planet. I think the issue deserves a guideline or an extension of the scope note. I do not see a conflict to continue from P56 with P46. The inference would be, that from feature "hair bundle Z" P46i forms part of feature "head X" P56i is found on object "statue X" follows "hair bundle Z" P56i is found on "statue X" with the same quantification. P46 on its own would not introduce a quantification constraint.
If we generalize P56 to E18 Physical Thing as domain, we loose the uniqueness of the carrying object.
Poated by Wolfgang Schmidle 14/02/2013
Thanks!
I hadn't thought of "P56 bears feature E25 (head) P46 is composed of E25 (hairstyle)", but now it seems obvious
We should add to scope note of P56 explanation how to describe subfeatures. Martin Doerr will write the guidelines.
28th CRM-SIG meeting 7/6/2013
Posted by Martin 30/9/2013
Old scope note:
This property describes an E26 Physical Feature found on an E19 Physical Object It does not specify the location of the feature on the object.
P56 bears feature (is found on) is a shortcut. A more detailed representation can make use of the fully developed (i.e. indirect) path from E19 Physical Object through P59 has section (is located on or within), E53 Place, P53 has former or current location (is former or current location of) to E26 Physical Feature.
An E26 Physical Feature can only exist on one object. One object may bear more than one E26 Physical Feature. An E27 Site should be considered as an E26 Physical Feature on the surface of the Earth.
My new scope note:
This property links an instance of E19 Physical Object to an instance of E26 Physical Feature that it bears .
An E26 Physical Feature can only exist on one object. One object may bear more than one E26 Physical Feature. An E27 Site should be considered as an E26 Physical Feature on the surface of the Earth.
An instance B of E26 Physical Feature being a detail of the structure of another instance A of E26 Physical Feature can be linked to B by use of the property P46 is composed of (forms part of). This implies that the subfeature B is P56i found on the same E19 Physical Object as A. P56 bears feature (is found on) is a shortcut. A more detailed representation can make use of the fully developed (i.e. indirect) path from E19 Physical Object through P59 has section (is located on or within), E53 Place, P53 has former or current location (is former or current location of) to E26 Physical Feature.
The above scope is accepted with the above changes.
29th CRM-SIG meeting, Heraklion, October 2013