| Re: Reference to PositioningSystem [message #1970 is a reply to message #1953] |
Mon, 17 September 2018 13:19  |
christian.rahmig
Messages: 436
Registered: January 2016
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Senior Member |
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Dear all,
Am 04.09.2018 um 11:34 schrieb Airy Magnien:
> [...] After review with RTM experts and
> talkback with C. Rahmig, this is where we are:
> Role 'positioningSystem' of class
> AssociatedPositioningSystem shall be made optional
> (cardinality 0..1 instead of 1). This leaves the possibility
> to omit redundant info. However it is not clear why this
> redundancy would cause a genuine problem. Our compromise
> solution is:
>
> - We insist that the relation shall me maintained, because
> it embodies the meaning of the AssociatedPositioningSystem
> class;
> - We recommend to use this redundancy for consistency
> checking;
> - We demand not to mix coordinates referring to different
> positioning systems in one same composition, because this is
> why the class "AssociatedPositioningSystem" has been
> introduced in the first place.
>
railML.org appreciates the decision of RTM Expert Group to make the
positioningSystem reference in class AssociatedPositioningSystem
optional. The resulting simplified solution has been implemented with
railML 3.1 beta 2 that is available in [1].
From modelling point of view, I generally prefer solutions without
redundancy in order to limit risk of inconsistencies. So, maybe the
question to be answered in future is whether the positioningSystem
reference shall be located in class AssociatedPositioningSystem OR in
PositioningSystemCoordinate.
[1] https://svn.railml.org/railML3/tags/railML-3.1-beta2/
Best regards
Christian
--
Christian Rahmig - Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Phone Coordinator: +49 173 2714509; railML.org: +49 351 47582911
Altplauen 19h; 01187 Dresden; Germany www.railml.org
Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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