DALIV12RFC < IVOA

IVOA Web>WebPreferences>DALIV12RFC (2025-11-05, GregoryMantelet) (raw view)
---+ DALI 1.2 Proposed Recommendation: Request for Comments

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The changes in DALI-1.2 are primarily the inclusion of additional xtypes that can be used to add extra type information to columns (e.g. in VOTable, tap\_schema) and how such values are serialised. Also in this update: VOSI-availability is now optional as it is considered deprecated and is being removed from VOSI-next and OpenAPI components for some key DALI parameters are included in the specification. As always, various ambiguous statements have been clarified where needed.

Latest version of DALI-1.2 can be found at:
   * https://www.ivoa.net/documents/DALI/20251024/index.html
   * see also the [[https://github.com/ivoa-std/DALI][GitHub repository]] for the latest change (since the RFC start)

---++ Reference Interoperable Implementations

The prototype CAOM-2.5 TAP service at CADC (https://ws.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/caom25/argus) makes use of the following xtypes (some from previous standards):
| *xtype* | *num_columns* | *standard* |
| multishape | 1 | PR-DALI-1.2 |
| timestamp | 21 | |
| adql:REGION | 1 | see note |
| clob | 1 | see note |
| multiinterval | 3 | PR-DALI-1.2 |
| point | 1 | |
| uri | 28 | PR-DALI-1.2 |
| shape | 2 | PR-DALI-1.2 |
| uuid | 14 | PR-DALI-1.2 |
| interval | 10 | |
*query:* select xtype, count(*) as num_columns from tap_schema.columns where xtype is not null group by xtype. <br /><b>note:</b> the adql:REGION value is still used for ivoa.ObsCore.s_region; the clob value is used for ivoa.ObsCore.access_url

The production CADC TAP service (CAOM-2.4) make use of some previously proposed/discussed xtype values and will be updated to DALI-1.2 in the near future.

---++ Implementation Validators

TOPCAT/STILTS: Validator and implementation updates to cover all !DALI 1.2 xtypes as appropriate, available in unreleased version at [[http://www.star.bristol.ac.uk/mbt/releases/topcat/pre/topcat-full_dali12.jar]]:
   * Validation:
      * =taplint= new stage =TYP= checks that column metadata is consistent with xtype declarations (e.g. =xtype="interval"= columns have =arraysize="2"=).
      * <code>votlint</code>/<code>taplint</code> checks VOTable column content is consistent with xtype declarations (e.g. =xtype="uuid"= values match =xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx=).
   * Implementation:
      * Topcat shape plotting upgraded to recognise new !DALI xtypes =range=, =shape=, =multishape=, =moc=.

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---++ Comments from the IVOA Community during RFC/TCG review period: %RED%2025-11-05 - 2025-12-17%ENDCOLOR%

The comments from the TCG members during the RFC/TCG review should be included in the next section.

In order to add a comment to the document, please edit this page and add your comment to the list below in the format used for the example (include your Wiki Name so that authors can contact you for further information). When the author(s) of the document have considered the comment, they will provide a response after the comment.

Additional discussion about any of the comments or responses can be conducted on the WG mailing list. However, please be sure to enter your initial comments here for full consideration in any future revisions of this document

   * Sample comment by TWiki.WikiName
      * Response (by TWiki.WikiName)

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---++ Comments from TCG member during the RFC/TCG Review Period: %RED%2025-11-05 - 2025-12-17%ENDCOLOR%

WG chairs or vice chairs must read the Document, provide comments if any (including on topics not directly linked to the Group matters) or indicate that they have no comment.

IG chairs or vice chairs are also encouraged to do the same, althought their inputs are not compulsory.

---+++ TCG Chair & Vice Chair

---+++ [[IvoaApplications][Applications Working Group]]

---+++ [[IvoaDAL][Data Access Layer Working Group]]

---+++ [[IvoaDataModel][Data Model Working Group]]

---+++ [[DistributedServicesAndProtocols][Distributed Services & Protocols Working Group]]

---+++ [[IvoaResReg][Registry Working Group]]

---+++ [[IvoaSemantics][Semantics Working Group]]

---+++ [[IvoaDCP][Data Curation & Preservation Interest Group]]

---+++ [[IvoaEducation][Education Interest Group]]

---+++ [[HEGroup][High Energy Interest Group]]

---+++ [[IvoaKDD][Knowledge Discovery Interest Group]]

---+++ [[IvoaOps][Operations Interest Group]]

---+++ [[IvoaRadio][Radio Astronomy Interest Group]]

---+++ [[IvoaSS][Solar System Interest Group]]

---+++ [[IvoaVOEvent][Time Domain Interest Group]]

---+++ [[IvoaStdsDocsProc][Standards and Processes Committee]]

---

---++ TCG Vote : %RED%2025-12-18 - 2026-01-08%ENDCOLOR%

If you have minor comments (typos) on the last version of the document please indicate it in the Comments column of the table and post them in the TCG comments section above with the date.

| Group | Yes | No | Abstain | Comments |
| TCG | | | | |
| Apps | | | | |
| DAL | | | | |
| DM | | | | |
| DSP | | | | |
| Registry | | | | |
| Semantics | | | | |
| DCP | | | | |
| Edu | | | | |
| KDIG | | | | |
| Ops | | | | |
| Radio | | | | |
| SSIG | | | | |
| TD | | | | |
| <span data-mce-mark="1"><nop></span>StdProc | | | | |

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Topic revision: r4 - 2025-11-05 - GregoryMantelet
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