Standardize output metadata fields for Nextstrain ingest

[joverlee521]

Originally discussed in Slack

In reviewing dengue ingest, I realized we don't have any central documentation on the standard Nextstrain metadata fields. There's currently SARS-CoV-2 docs on it's metadata fields, but it has a lot of SC2/GISAID specific language. (As it should, since that's what it was written for!)
Should we add a metadata section to our top level Data formats page that is focused on standard fields that we use from public data/NCBI? I think with standardizing ingest, we should also have a set of standard metadata fields that is expected for all of our public pathogen metadata. Each pathogen will most likely have additional pathogen-specific fields on top of the standard fields and they would be documented within individual pathogen repos.

---

Next steps

1. Compare the fields used in our current public metadata TSVs and propose a list of standardized fields.

• ncov - s3://nextstrain-data/files/ncov/open/metadata.tsv.zst
• mpox - s3://nextstrain-data/files/workflows/mpox/metadata.tsv.gz
• rsv - s3://nextstrain-data/files/workflows/rsv/a/metadata.tsv.gz

2. Define schema for the metadata TSV. @tsibley suggested that this can be a constrained form of JSON Schema or we can look into existing tabular schemas.
   • Frictionless Data's Table Schema could be useful. They have a Python framework for frictionless that can use the schema to validate files.

[joverlee521]

As @j23414 commented in a separate PR, we've had internal discussions on whether the NCBI accession column should be
accession or genbank_accession.

The general consensus in a previous dev chat was that it's better to be more specific and use genbank_accession. However if the data needs to be merged with private data or data from other sources, then there needs to be a general accession column.

[joverlee521]

Brought up in Nextstrain office hours today to consider standardizing with NCBI standards in mind, specifically with regards to the One Health Enteric Metadata standards.

@huddlej also pointed to the PHAGE SARS-CoV-2 metadata standards as another potential reference.