TT AvData Discussion 2025 Jun 4 - wmo-im/iwxxm GitHub Wiki

Details

2025-Jun-4, 12:00-14:10 UTC, Microsoft Teams

Agenda

  1. IWXXM 2025-2:
    • Review consolidation of wmo-im/iwxxm and wmo-im/iwxxm-codelists GitHub repositories (Choy and Anna)
    • Demonstrate schematron validation using code lists RDF files with individual entity having applicable IWXXM version(s) (Choy)
      • Decide whether we need gradual or direct transition to consolidate code lists
    • Review on changes made in IWXXM 2025-2RC2 (Choy)
      • Decide who to conduct further tests on adequacy of the schemas and schematrons in terms of representation and validation
  2. Draft technical guidance on encoding with IWXXM (Sunny)
  3. Updates to the discussion on authorization of changes to abbreviated headings (Anna)
  4. Preparation for development of IWXXM to support AMOIS, AMFIS and HWIS (Dirk and Choy)

Notes

  • Choy opened the meeting with greetings to all
  • Choy described the work done so far on the
    • consolidation of the iwxxm codelists - see issue 355
    • code schematrons and versioning issue 354
  • The meeting has a general understanding that the transition from existing codelists (306, 49-2, common and bufr4/codeflag) to their consolidation form under iwxxm will be:
    • The origin of the codelists are those CSV files on the GitHub repository.
    • The TTL files generated from the CSV files will be used to update the WMO Codes Repository (except possibly those under common and bufr4/codeflag as they are maintained by other teams)
    • The RDF files generated will be used by iwxxm.sch for validation
    • Existing IWXXM packages will, if they are doing so right now, continue to use the 306, 49-2, common and bufr4/codeflag codelists and new packages will use their consolidated versions under iwxxm
    • To make sure that columns in the CSV files are aligned with those on the WMO Codes Registry, Anna will give her advise
    • Boris will see if he could dig out the location or even the XSD files themselves for Choy to validate the RDF/XML files generated, especially with the addition of owl:versionInfo to act as tags to indicated applicable IWXXM versions of codelists and their entities. The following are the namespaces of the schemas being used: 
      <rdf:RDF
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
  xmlns:skos="http://www.w3.org/2004/02/skos/core#"
  xmlns:reg="http://purl.org/linked-data/registry#"
  xmlns:ldp="http://www.w3.org/ns/ldp#"
  xmlns:dct="http://purl.org/dc/terms/"   -> http://schemas.opengis.net/csw/2.0.2/rec-dcterms.xsd
  xmlns:owl="http://www.w3.org/2002/07/owl#"   -> https://www.w3.org/2009/09/owl2-xml.xsd
>
    • Jan will see if he could give some hint on improving the coding of the schematron rule to check the existence of a codelist entry and the applicable IWXXM version (see post)
  • Boris explained the proposal on geometry for space weather and the team discussed options - see issue 351
  • Boris talked about how Mercator lines will be replaced by geodesic lines
    • He showed some options in GML and noted that this would change how polygons are encoded
    • The team discussed the challenges and solutions
    • The team decided to add examples for 2025-2 with geodesic encoding and promulgate the benefits of describing accurately the geometry of phenomena on the surface of the globe
    • The latter of the above should tie in with the preparation to amend existing ICAO documentations Once the requirements are in place in a few years' time, we may consider adding schematron rules to mandate the use of geodesic representation
  • Jan brought up an issue faced by one of their clients who are not able to representing variable wind the TREND forecast section of METAR/SPECI.
    • The meeting aware this is long standing issue of the TAC template; variable wind can be represented in the observation section of METAR/SPECI and TAF
    • To change IWXXM METAR/SPECI the TAC template will need to be changed (now in PANS-MET) in first place which requires a State to raise in relevant ICAO working group(s), considered by MET/P and approval by ANC.
    • A pragmatic way is to see if the extension feature in IWXXM can be used to include this information. Choy mentioned that the ICAO Asia and Pacific Region (APAC) has created a regional extension to FIXM so creating a regional or even global extension to augment existing models is not unacceptable by the community. Choy will take a look at this. If feasible and the team agrees with the kind of extensions to be introduced he will bring back for ICAO WG-MIE's further discussion
  • Choy will finalize the schemas and send out email when ready for review
  • Sunny demoed his GitHub repository of guidance developed with ascii docs, with the goal of making it available on schemas.wmo.int or community
    • Choy indicated that this will be the place to include practical guidance on encoding IWXXM messages. Things like geodesic representation should be included when becoming mature
  • Dirk talked about the development of AMOIS, AMFIS and HWIS and the rough schedule for Europe to develop the new SWIM information services which requires IWXXM release candidates to support the provision of such information before 2027
    • A meeting of ICAO WG-MIE, WG-MRAD and TT-AvData chairs will take place on 18 June to see how to proceed
    • Anna would like to confirm if TT-AvData can officially participate in the development work
    • Choy asked and all of the team members showed interest to be involved
  • The team scheduled the next two meetings with a view to finalize the submission of 2025-2RC2 by the end of June for approval through FT
  • Paul noted that TSML is working on a 2.0 release with CSV and JSON representations
    • Boris highlighted the pros and cons of XML and JSON representations, and opted that XML excels in one aspect - that it has a more formal way to validate instances (with schema + schematron) and has a number of tools to choose from.
    • Choy indicated that JSON is best for the passing of information in the last mile (i.e. service provider to end user) where the end users can choose the level of information and service qualities according to their needs (and may be the price they are paying too) while XML is more suitable for producers and consumers/brokers which requires the highest level of information quality. Seamless conversion between XML and JSON may be the key development direction especially at the servers where end users get in touch with

Actions

  • Anna to advise on the columns of the CSV files
  • Boris to see if he has information on the location (or even the XSD files) of schemas being used in the RDF/XML files
  • Jan to give some hints on the coding of the schematron rule to check both a codelist entry and applicable IWXXM version
  • Choy to investigate the use of extension to represent variable wind in TREND forecast
  • Boris open issue on Geodesic (https://github.com/wmo-im/iwxxm/issues/356)

Next Meetings

  • 13 June 2025
  • 25 June 2025

Invitees / Attendance

Name Country/Affiliation Attendance
Boon-leung CHOY (Chair) Hong Kong, China X  
Wilberforce KIKWASI (Member) Tanzania  
Jan KOROSI (Member) HMEI/IBL  X
Mark OBERFIELD (Member) USA  (Retired)
Raquel SALAZAR (Member) Costa Rica  
Boonchai TEPYOSE (Member) Thailand  
Dirk ZINKHAN (Member) Germany  X
Albert MOLOTO (Member) South Africa  
Shan CAO (Member) China X
Sunny CHAN (Guest) Hong Kong, China X
Paul HERSHBERG (Guest) USA  X
Anna MILAN (Secretariat) WMO X
Martin Michalek (Guest) HMEI/IBL X
Boris BURGER (Guest) HMEI/IBL X