| [railML3] Order of geometricCoordinate attributes [message #4157] |
Fri, 04 September 2026 19:37  |
Thomas Nygreen
Messages: 137
Registered: March 2008
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Senior Member |
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Dear community!
I have found that the current documentation of the x, y and z attributes of geometricCoordinate are not in line with positioning examples in the wiki nor with how they are interpreted by railVIVID. Therefore I would like to ask for feedback from the community about your interpretation and use of these attributes. These attributes are not documented in railML 3.1, but in 3.2 since SR2 and in 3.3 since its first release, they are documented as x = longitude, y = latitude and z = altitude.
The order of axes differs between coordinate reference systems (CRSs), and the very common WGS 84, in the way it is defined by EPSG, has latitude as the first coordinate. This is an unending source of confusion when it comes to storing and communicating coordinates, and is not a railML-specific issue. The question is how we deal with it in railML. Mainly there are two approaches: use a fixed order or follow the order given by the referenced CRS. For more information I refer to [1], and I ask: How do you currently use the x and y attributes of geometricCoordinate, and which approach do you prefer for their definition in railML?
[1] https://development.railml.org/railml/version3/-/work_items/ 788
Best regards,
Thomas
Thomas Nygreen – Common Schema Coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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| Re: [railML3] Order of geometricCoordinate attributes [message #4168 is a reply to message #4160] |
Mon, 07 September 2026 12:16  |
christian.rahmig
Messages: 592
Registered: January 2016
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Senior Member |
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Dear all,
I agree with Mathias here: Let's use the order of coordinates as defined by the CRS.
But be careful: What do we do with CRS that define a height information only. Is this then coordinate x (and y and z are empty) or is it coordinate z (and x and y are empty) in our railML data model?
Best regards
Christian
Christian Rahmig – Infrastructure schema coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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| Re: [railML3] Order of geometricCoordinate attributes [message #4235 is a reply to message #4168] |
Fri, 09 October 2026 14:17 |
christian.rahmig
Messages: 592
Registered: January 2016
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Senior Member |
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Dear all,
any opinions on the question I raised in my previous post: What do we do with CRS that define a height information only. Is this then coordinate x (and y and z are empty) or is it coordinate z (and x and y are empty) in our railML data model? (see [1] for details)
My preference would be "x", because then we can make at least one coordinate mandatory and the //geometricCoordinate element won't be empty by schema.
[1] https://development.railml.org/railml/version3/-/work_items/ 788
Best regards
Christian
Christian Rahmig – Infrastructure schema coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
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| Re: [railML3] Order of geometricCoordinate attributes [message #4240 is a reply to message #4235] |
Thu, 15 October 2026 15:46 |
Stefan Hubrig
Messages: 9
Registered: October 2018
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Junior Member |
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Hello all,
or:
having the (XML) choice of either
- geometricCoordinate - where x and y stay mandatory or
- sth like geometricHeight - where there is z (or height/value)
This could also make it easier to read/understand.
Best regards,
Stefan
Stefan HUBRIG
Software Engineer
Hitachi Rail
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