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Spatial reference system: encoding example with authority - is this still valid? #28

Closed Sgaff closed 1 week ago

Sgaff commented 3 years ago

The guidance text for https://www.agi.org.uk/gemini/40-gemini/1062-gemini-datasets-and-data-series/#17 Spatial Reference System states the class comprises two elements, a code and a codespace. This is in keeping with the guidance from INSPIRE (p70 of inspire-tg-metadata-iso19139-2.0.1%20(1).pdf)

However, in the encoding guidance we provide for this element, we display an encoding we state is valid which is spatial reference with authority, This uses CI_Citation for the authority part and, while valid in ISO, does not meet the INSPIRE requirements.

Should we keep this example, or, as we have decided to merge GEMINI and UK INSPIRE, should we remove it?

Sean Gaffney MEDIN

PeterParslow commented 3 years ago

@Sgaff could you label this? That should help us as we begin to resolve issues

PeterParslow commented 3 years ago

I suggest we remove the example that is not valid w.r.t. INSPIRE

PeterParslow commented 3 years ago

2021-07-01: Increasingly, we are considering GEMINI being used for things other than INSPIRE, but we do say that a GEMINI record is INSPIRE compliant.

Delete the example (and therefore renumber some others).

PeterParslow commented 3 years ago

Email discussion with Sean after the meeting (copied to all): I think it concluded that the example does actually meet the INSPIRE requirements: it provides the code, using an Anchor (TG Requirement 2.1), and does not give a codeSpace (TG Requirement 2.2 second paragraph 'shall not').

Providing the 'authority' is extra to this, allowable under https://www.agi.org.uk/gemini/40-gemini/1051-uk-gemini-v2-2-specification-for-discovery-metadata-for-geospatial-resources/#extended

It would be good to change the description of the example to state this: i.e. change

Example Three - encoding example with authority

to

Example Three - encoding example with ISO 19115 authority, as generally described Extended metadata/additional elements

PeterParslow commented 3 years ago

2021-07-16: we realised that the element Guidance doesn't actually say what to do if the CRS is one of the INSPIRE faults. Add a bullet item between

Add an element Comment mentioning the optional additional "ISO 19115 authority, as generally described Extended metadata/additional elements"

Move element Comment 1 ("Only coordinate reference systems identifiers specified in a well-known common register shall be used") up to the Domain, as it is a rule.

PeterParslow commented 2 years ago

Doing this has highlighted to me that the actual wording of INSPIRE TG requirement metadata/2.0/req/isdss/crs-id differs from its example & the approach everyone uses.

The requirement actually says:

If the coordinate reference system is listed in the table Default Coordinate Reference System Identifiers in Annex D.4, the value of the HTTP URI Identifier column shall be used as the value of _gmd:referenceSystemInfo/gmd:MD_ReferenceSystem/ gmd:referenceSystemIdentifier/gmd:RSIdentifier/gmd:code element.

But the example takes the sensible approaching of putting the HTTP URI in the gmx:Anchor link attribute, and the "well-known" EPSG code as the value of the code element. Taking the general approach that a URI is more authoritative than a character string, I'll stick with that.

Perhaps I'm just interpreting 'value of ... element' in a stricter XML sense than the INSPIRE TG!

I have raised this as https://github.com/INSPIRE-MIF/technical-guidelines/issues/7

PeterParslow commented 2 years ago

Fixed on my laptop/Onedrive

nmtoken commented 2 years ago

related https://github.com/agiorguk/gemini-schematron/issues/7 ?

PeterParslow commented 2 years ago

related agiorguk/gemini-schematron#7 ?

Same element, but I don't think it's a similar issue. That one was about accepting URNs instead of HTTP URIs. This one was originally about providing the additional "authority" information - which would be possible with either encoding. The related INSPIRE-MIF/technical-guidelines#7 is about the "clash" between the wording of their requirement when referencing one of the CRSs in their default list (using its HTTP URI), and the example.

PeterParslow commented 9 months ago

https://github.com/INSPIRE-MIF/technical-guidelines/issues/7 fixed in August 2022.

As at October 2023, The examples had already been relabelled in the live GEMINI text.

Other changes in https://github.com/agiorguk/gemini/pull/124

archaeogeek commented 6 months ago

@archaeogeek to change description for example 3 to Example Three - encoding example with ISO 19115 authority, as generally described Extended metadata/additional elements