CAOM Model Integration

The Common Archive Observation Model is widely used in the Astronomical community, and there is interest in making it an IVOA standard. This project will work the details of how to integrate the CAOM model into the IVOA data model ecosystem.

Meetings (reverse order)

• 2025 Mar 12: CaomIntegrationMtgNotes20250312
• 2025 Feb 20: CaomIntegrationMtgNotes20250220
• 2025 Feb 12: CaomIntegrationMtgNotes20250212

High-Level Roadmap

1. Representation as VO-DML model
   1. size-dependent floating point types (double)
   2. Shape concept as base type (consolidate with DALI)
2. Resolve Model Overlap
   1. DatasetMetadata vs Observation
      1. dataset/dataproduct - artifact/part: description of an entity which consists of multiple files/blocks/entities. e.g. Measurement set; Event list + ARF.
   2. Characterisation elements
3. Update Model Document

Decision Points

• size-specific extensions to ivoa:real
  • these could be added to the base types model; with description recommending modelers use the most-generic representation which satisfies the requirements.
    this would need review/discussion in the DM group, which may get some push-back from the idea that 'real' is size-agnostic and the specific size implemented is a serialization/implementation choice. If that is the case; these extensions could be defined in CAOM itself; or identified as some sort of constraint on the ivoa:real within that model.
• add Shape concept to base model
  • the concept is better handled outside the base types model. CAOM will extract the concept to an external model, and import it.
  • discussion will continue regrading how the Shape model will evolve given the need for more complete representations for other cases ( Region, Intervals, Mango, etc )
• Characterization content in CAOM
  • We don’t need both CAOM characterisation elements AND Characterisation model.. they should be integrated at some level. (TBD)
    • the primary use case for the Characterisation model is in support of ObsCore, which is most properly described as a view of CAOM
    • the Characterisation representations within CAOM are sufficient to satisfy that use case.

Related GitHub Repositories/Issues

• CAOM: https://github.com/opencadc/CAOM
  • Attribute multiplicity > 1: Issue 28 and VO-DML issue 69
  • Base datatypes for shape and interval: prototype in PR-31
• Dataset Metadata: https://github.com/ivoa-std/DatasetDM
• IVOA base types model: https://github.com/ivoa/vo-dml/tree/master/models/ivoa

Related Presentations