Add samples from IGSN to the map

[nuest]

https://ev.igsn.org/

👉 https://www.geosamples.org/ (https://web.archive.org/web/20250519213110/https://www.geosamples.org/)

Find IGSNs without the :tba placeholder: https://commons.datacite.org/doi.org?query=igsn+-tba&resource-type=physical-object&cursor=2

Use 2025 as a filter to find some from GFZ.

There we finally get coordinates: https://dataservices.gfz-potsdam.de/igsn/esg/index.php?igsn=GFRKA00ER

GFZ samples could also be retrieved directly from https://dataservices.gfz-potsdam.de/igsn/

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Can match IGSNs from full text? https://ev.igsn.org/resources/using-igsn-in-publications Ideally use a database that already did that...

[nuest]

Having the samples even in the background could be a way of georeferencing papers - we just need to check whether a paper links to samles, ideally via some API, or (with a lot more effort) by extracting sample identifiers from the full text.

[nuest]

Are samples also "works" ? Maybe not, so elaborate on options how to model these different kinds of resources (especially at the Django level).

[nuest]

Research on the DataCite IGSN corpus size and metadata quality (13.4 M geolocated points; GFZ coords not in DataCite; DataCite relatedIdentifiers is the source of truth for sample↔work links) is captured in #263, along with candidate scaling approaches (server-side clustering primary). The initial implementation here will use a bounded subset.