Registry interoperability
Registries are only as useful as the links between them. A record that cannot be referenced stably, exported faithfully or read by another system becomes an island, and islands drift apart. This page sets out how stable references, persistent identifiers, metadata crosswalks, export formats and interface semantics let registries exchange records without losing meaning, and how interoperability fails through link rot, lossy mapping and undocumented change.
Interoperability console
Registry interoperability · Crosswalk · Profile v3
Field mappings
| identifier | id | copy | Pass |
| evidence_label | quality.label | enum map | Pass |
| licence | rights.licence | SPDX id | Ambiguous |
| version | version | semver | Pass |
Conformance
Fig.Interoperability console. Design wireframe with placeholder names and illustrative values, not a record or a live system.
The short answer.
Registry interoperability is the ability of registries to exchange records without losing meaning, through stable references, persistent identifiers, metadata crosswalks, standard export formats and documented interfaces. It fails through link rot, lossy mapping between schemas and interface changes made without notice.
People and hazards in World.
For registry interoperability, in GCRI's spatial-intelligence reading, the map opens on true-colour imagery, night lights and population density with relief in 3D and true colour from NASA GIBS, framed on World; every other NASA layer, live feed and forecast waits in the layer list.
The interactive map needs JavaScript; the layer list and sources are below.
Layers 3
People and hazards, for this page
Keyboard, with the map focused
Hold Ctrl or ⌘ and scroll to zoom
Latest available
NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
Loading the latest NASA imagery.
Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.
For registry interoperability, in GCRI's spatial-intelligence reading, the map opens on true-colour imagery, night lights and population density with relief in 3D and true colour from NASA GIBS, framed on World; every other NASA layer, live feed and forecast waits in the layer list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.
Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · GDACS · Copernicus Sentinel-2 L2A · NASA HLS S30Sources and licences
- We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). CC BY 4.0
- MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
- © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). ODbL
- Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
- Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
- Globe: MapLibre GL JS 6.9.1, BSD-3-Clause, © MapLibre contributors.
- Live: GDACS (EC JRC / UN OCHA) Events are indicative, not official warnings.
- Observed (EO): Copernicus Sentinel-2 L2A (contains modified Copernicus Sentinel data 2026), Microsoft Planetary Computer
- Observed (EO): NASA HLS S30 (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).
- Optional layers (35 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.
Layers and dates
- True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
- Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
- Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
- Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
- Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
- Enhanced vegetation index, rolling 8 days: MODIS Terra EVI, NASA LANCE · 13 Oct 2026
Registry interoperability: how the risk develops.
Stable references, exports and API semantics. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Link rot and content drift
Location links break when sites are reorganised, and links that still resolve may point to changed content. Without persistent identifiers and archived snapshots, references silently stop meaning what their authors intended.
Lossy crosswalks
Mapping one schema to another drops fields with no equivalent and flattens distinctions, such as several contributor roles folded into one. Round trips lose information, and each exchange makes the copies less alike.
Undocumented interface change
An interface changes a field's meaning, format or default without a version or notice. Consumers keep parsing successfully while reading the wrong thing, and the errors surface far from the change that caused them.
Identity collision across registries
The same organisation, person or work carries different identifiers in different registries, or a local identifier is reused for different things. Joins across systems then merge what is distinct or split what is one.
Terms used on this page.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Metadata crosswalk | A mapping between the fields of two metadata schemas, showing what translates and what is lost. |
| Link rot | The decay of web links as targets move or disappear. |
| DCAT | The W3C Data Catalog Vocabulary for describing datasets and data services in catalogues. |
What is measured, and how well.
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Identifier resolution success | share of resolution probes | daily | Resolver probes | OBSERVED |
| Interface availability | share of time available | continuous | Availability monitoring | OBSERVED |
| Export schema conformance | share of exported records validating | per release | Schema validation | OBSERVED |
| Crosswalk coverage | share of fields mapped to the target schema | per release | Crosswalk register | DECLARED |
| Round-trip fidelity | share of records returned intact | per release | Round-trip test | OBSERVED |
| Broken outbound references | share of references | monthly | Link checking | OBSERVED |
| Deprecation notice period | days | per interface change | Change log | DECLARED |
| Records linked to external persistent identifiers | share of records | monthly | Identifier reconciliation | OBSERVED |
From sources to decisions.
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Where the evidence comes from.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| DCAT version 3 | A vocabulary for catalogues, datasets, data services and versions in exchange | W3C document licence, free to implement |
| Schema.org | A shared vocabulary for embedding structured metadata in web pages | CC BY-SA for the vocabulary |
| OAI-PMH | A protocol for harvesting metadata from repositories | Open specification |
| Scholix link exchange | A framework and services for exchanging links between literature and data | CC0 for link metadata |
| re3data registry of research data repositories | Descriptions of repositories with their standards, identifiers and access policies | CC0 for metadata |
| FAIRsharing | A curated registry of standards, databases and policies and their relationships | CC BY-SA for content |
| OpenAIRE Graph | An open graph linking publications, data, software, projects and organisations across sources | CC BY |
| OpenAPI Specification | A standard description format for HTTP interfaces | Open specification, Apache licence |
Who decides, and what the evidence serves.
Nexus Registry prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Registry and repository managers | Which schemas, identifiers and interfaces to support, and on what deprecation timetable | Crosswalk coverage, round-trip losses and the consumers depending on each interface |
| Research infrastructure funders | Whether to fund integration with an existing registry or a new parallel system | Interoperability measures, standard conformance and existing link coverage |
| Data stewards | Whether imported records can be merged with local ones | Identifier matches, crosswalk losses and conflicts between sources |
| National statistics offices and public data portals | Whether registry exports can feed official catalogues | DCAT conformance, licence metadata and the stability of identifiers |
Outputs this topic produces
- Stable references for every record, resolving to a current view and its versions
- Exports in documented formats with schema files and published crosswalks
- An interface change log with version numbers and deprecation notices
- Round-trip tests against external registry schemas with every loss listed
What experts ask about interoperability.
- How should identifiers from different registries be linked without copying records?
- Which open formats preserve meaning, provenance and rights when records are exported?
- How are field meanings documented so that two systems agree on what a value means?
- How do interfaces signal that a record has changed or been withdrawn?
- How are schema changes made without breaking systems that depend on them?
Why exchange fails.
Interoperability fails at three levels. Technically, formats and protocols do not match. Semantically, the same field name means different things, so a status of active or a date of publication is silently misread. Organizationally, no one is responsible for keeping links current, so references decay. Semantic failures are the hardest to see because the data moves without error and is simply wrong at the destination.
Shared vocabularies address these. Linked-data formats such as JSON-LD carry meaning with the data, catalogue vocabularies such as DCAT describe datasets, and W3C PROV carries lineage. Methods from data engineering, interoperability and stewardship cover these standards and their trade-offs. The Registry's planned interfaces are described on interfaces.
Designing for exchange.
- 01
Link, do not copy
Records refer to external registries by identifier, preserving aliases so an external reference still resolves.
- 02
Documented semantics
Each field's meaning, allowed values and version are published alongside any interface.
- 03
Versioned schemas
Schema changes take a new version, and older records keep the schema they were made under.
- 04
Limits
Interoperability depends on partners maintaining their own records. Mappings between vocabularies lose nuance, and an export carries rights obligations that the receiving system must honour.
How it is studied, and what the methods cannot say.
- Data engineering, interoperability and stewardshipSchema-validated ingestion · Persistent identifier reconciliation · Lineage capture in pipelinesApplied here
- Cybersecurity and cryptographyTamper-evident record history · Signed exports and releases · Threat modelling of edit pathsApplied here
- Digital identity and public digital systemsIssuer authentication and authority · Contributor disambiguation by the personApplied here
Questions and answers.
What makes a reference stable?
Why not just use web addresses?
What is a crosswalk?
How are interface changes announced?
Is there an interface I can use now?
Will exports include restricted records?
Can my registry link to Nexus records?
Around Nexus Registry.
Bring your expertise to this field.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.