Description: The process of sampling, observing and analyzing physical samples is not unique to the geosciences. Physical sampling (taking specimens) is a fundamental strategy in many natural sciences, typically to support ex-situ observations in laboratories with the goal of characterizing real-world entities or populations. Observations and measurements are made on individual specimens and their derived samples in various ways, with results reported in research publications. Research on an individual sample is often published in numerous articles, based on multiple, potentially unrelated research programs conducted over many years. Even high-volume Earth observation datasets are proxies of real world phenomena and require calibration by measurements made on position located, well described physical samples. Unique, persistent web-compatible identifiers for physical objects and related sampling features are required to ensure their unambiguous citation and connection to related datasets through web identifiers. Identifier systems have been established within specific domains (e.g., bio, geo, hydro) or different sectors (e.g., museums, government agencies, universities), including the International Geo Sample Number (IGSN) in the geosciences, which has been used for rock, fossil, mineral, soil, regolith, fluid, plant and synthetic materials. IGSNs are issued through a governance system that ensures they are globally unique. Each IGSN directs to a digital representation of the physical object via the Handle.net global resolver system, the same system used for resolving DOI. To enable the unique identification of all samples on Planet Earth and of data derived from them, the next step is to ensure IGSNs can either be integrated with comparable identifier systems in other domains/sectors, or introduced into domains that do not have a viable system. A registry of persistent identifier systems for physical samples would allow users to choose which system best suits their needs. Such a registry may also facilitate unifying best practice in these multiple systems to enable consistent referencing of physical samples and of methods used to link digital data to its sources. IGSNs could be extended into other domains, but additional methodologies of sample collection, curation and processing may need to be considered.

Description: Persistent unique identifiers (PID) are a critical element in digital research data infrastructure to unambiguously identify, locate, and cite digital representations of a growing range of entities – publications, data, instruments, organizations, funding awards, field programs, and others. The IGSN was developed as the International Geo Sample Number to provide a persistent, globally unique, web resolvable identifier for physical samples. IGSN is both a governance and technical system for assigning globally unique persistent identifiers to physical samples. Even though initially developed for samples in the geosciences, the application of IGSN can be and has already been expanded to other domains that rely on physical samples and collections. This paper describes the current architecture and technical implementation of IGSN, how IGSN relates to other sample identifiers, and how its technical systems are supported by an international governance structure.