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[railML3] Proposal of a semantic constraint for mileageChange [message #3075] Thu, 20 April 2023 12:33 Go to next message
Milan Wölke is currently offline  Milan Wölke
Messages: 142
Registered: April 2007
Senior Member
Hi all,

I would like to propose the introduction of two new semantic constraints for the mileageChange element of the railML 3 infrastructure.

First one would restrict the scope of referencing spot locations with the "from" and "to" attribute to those spot locations that are enclosed by the mileageChange element that carries the attributes.

The second one would ensure that both these spot locations actually refer to the same net element.

Both these constraints should not have a negative impact on any existing interfaces as the described is actually what one would expect anyway. However, I would still propose formalizing this in order to make life easier for importing system.

What does the community think?

Best regards, Milan


Milan Wölke – Timetable scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
Re: [railML3] Proposal of a semantic constraint for mileageChange [message #3081 is a reply to message #3075] Thu, 04 May 2023 09:00 Go to previous messageGo to next message
christian.rahmig is currently offline  christian.rahmig
Messages: 447
Registered: January 2016
Senior Member
Dear Milan,

although I am not "the community" I understand your argumentation and support your SemCon proposal. So, if there are no further replies by end of next week, I suggest to adapt the SemCons accordingly.

Best regards
Christian


Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
Re: [railML3] Proposal of a semantic constraint for mileageChange [message #3085 is a reply to message #3081] Wed, 10 May 2023 15:55 Go to previous messageGo to next message
Thomas Nygreen is currently offline  Thomas Nygreen
Messages: 68
Registered: March 2008
Member
Dear all,

I think we should be very careful about assuming what (every)one expects. Why would one expect never to find a netElement that is split at a mileage change? In that case, would it not be expected that the mileage change refers to the end of one and the start of the other? Or should this be modelled without any mileage change?

Why do we need the attributes from and to at all? Is it not given that the spot locations given for the mileage change represent the same location? And the type attribute takes care of the order.

Best regards,
Thomas


Thomas Nygreen – Common Schema Coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
Re: [railML3] Proposal of a semantic constraint for mileageChange [message #3090 is a reply to message #3085] Thu, 25 May 2023 21:01 Go to previous messageGo to next message
christian.rahmig is currently offline  christian.rahmig
Messages: 447
Registered: January 2016
Senior Member
Dear Thomas,

interesting thoughts, thank you.

For the first question regarding the location of a mileage change on more than one netElement, I would ask the community for their opinion: Do you want to model mileage changes on two netElements?

Concerning the second point: Yes, the attribute <mileageChange>@type already tells you what to expect: a gap or an overlap. Therefore, the attributes seem to be indeed redundant.

As usual I appreciate any kind of further opinion from the community...

Best regards
Christian


Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
Re: [railML3] Proposal of a semantic constraint for mileageChange [message #3093 is a reply to message #3085] Wed, 31 May 2023 16:11 Go to previous messageGo to next message
Thomas Langkamm is currently offline  Thomas Langkamm
Messages: 25
Registered: April 2019
Junior Member
I know mileage changes only as a spot object. We have a point in the network at which we change the mileage. So I would indeed question if we need "from" and "to" as well. After all, mileages are like coordinate systems for a railway -- how would you describe a point between "from" and "to" with a single mileage?

Which would also take care of the question if we could reference 2 or more netElements.
Re: [railML3] Proposal of a semantic constraint for mileageChange [message #3126 is a reply to message #3093] Mon, 04 September 2023 14:39 Go to previous message
christian.rahmig is currently offline  christian.rahmig
Messages: 447
Registered: January 2016
Senior Member
Dear Thomas, dear all,

I conclude from your remarks and feedback that the <mileageChange> attributes @from and @to shall be marked deprecated for future railML 3 versions, because they are redundant. I created a Git issue here [1].

[1] https://development.railml.org/railml/version3/-/issues/517

Best regards
Christian


Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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