1. 1 Digital Object Identifiers for NASA EOSDIS data April 17, 2014 Nate James NASA-GSFC ESDIS Project Nate James, ESDIS – Team Lead/Presenter Lalit Wanchoo, ADNET Systems Inc. Beth Stolte, Columbus Technologies

2. What is a Digital Object Identifier? 2 A DOI is … A unique identifier that Can be embedded in a permanent URL which Resolves to a web page which –Describes a data product and –Credits the product creator/steward for their work DOI string consists of two parts - doi:[prefix]/[suffix] Prefix is 10.5067 –“10” represents the DOI registry identifier –“5067” represents the DOI registrant (NASA-ESDIS) Suffix is123 –“123” uniquely identifies the data object being cited DOI URL resolves to a web page that describes the cited object.

3. What is a Digital Object Identifier? 3 Unique alphanumeric string used as an identifier for citing digital objects in literature. DOI string consists of two parts - doi:[prefix]/[suffix] Prefix is 10.5067 –“10” represents the DOI registry identifier –“5067” represents the DOI registrant (NASA-ESDIS) Suffix is123 –“123” uniquely identifies the data object being cited DOI URL resolves to a web page that describes the cited object. DOI Name ExampleDOI Permanent URL Example doi:10.5067/123http://doi.dx.org/10.5067/123

4. What is a Digital Object Identifier? Internet infrastructure: The DOI® system and the Handle System: An internet resolution service for unique and persistent identifiers of digital objects Owned by International DOI Foundation (IDF) www.doi.org.www.doi.org Implementation infrastructure: Internet Service Provider - DOI Handling System dx.doi.org Domain Registrant - EZID (subscription provider) DOI Registrant (NASA-ESDIS: 5067) Citation and location information can be updated as frequently as desired by the Registrant subscription holder Registry guideline is one DOI per data object but multiple registrations of ‘similar’ data are not precluded Existing DOIs may be migrated to new or different Registrant Agent and/or owner at any time 4

5. DOI Characteristics DOIs Promise to be… Permanent/Persistent Once registered, the DOI never changes Actionable URL Link resolves to actively maintained web page with additional information. Informative Links to detailed descriptions of NASA archived datasets Uses “Smart” Landing Pages digitally tagged to enhance search and discovery Supports reproducibility and integrity of scientific results Encourages citations by crediting data creators and stewards 5

6. NASA-ESDIS DOI Example Product DOI Name: DOI:10.5067/MEASURES/GSSTF/DATA302 DOI System Internet resolution service: http://dx.doi.org/10.5067/MEASURES/GSSTF/DATA302 Leads to DOI landing page for that product DataCite citation service (http://crosscite.org/citeproc/) can be used to get well-formatted citations for a given DOI for various publications. For example, above DOI leads to following citation in AGU Journal format:http://crosscite.org/citeproc/ Shie, C.-L., K. Hilburn, L. S. Chiu, R. Adler, I-I Lin, E. Nelkin, J. Ardizzone, and S. Gao (2012), NCEP/DOE Reanalysis II, for GSSTF, 0.25x0.25 deg, Daily Drid, V3, (GSSTF_NCEP), doi:10.5067/MEASURES/GSSTF/DATA302. 6

7. EOSDIS DAACs and SIPSs Science Data Centers (aka Distributed Active Archive Centers – DAACs), collocated with centers of science discipline expertise, archive and distribute standard data products produced by Science Investigator-led Processing Systems (SIPSs)

8. NASA-ESDIS Goal 8 Assign and register DOI’s for all datasets managed by EOSDIS

9. DOI Status 9

10. NASA-ESDIS Role 10 Develop guidelines, procedures and processes for registration of DOIs Quality Check the DOI Metadata Reserve DOIs with ESDIS Register DOIs with EZID Update Information with EZID Maintain DOI records (via wiki)

11. ESDIS DOI Registration Metadata DOI Mandatory Metadata Identifier (DOI Name) Creator Name Title Publisher Publication Year URL DOI Additional Information Mission/Program name Instrument/Project Name DOI Information Provider Contact Name Contact Email Landing Page Agency Contact Name Contact Emailil 11 Identifier (DOI Name) Creator Name Title Publisher Publication Year URL DOI Mandatory Metadata Provider Contact Name Contact Email Landing Page Agency Contact Name Contact Email DOI Additional Information DOI Registration Metadata Requirements Identifier (DOI Name) Creator Name Title Publisher Publication Year URL DOI Mandatory Metadata Provider Contact Name Contact Email Landing Page Agency Contact Name Contact Email DOI Additional Information DOI Registration Metadata Requirements Identifier (DOI Name) Creator Name Title Publisher Publication Year URL DOI Mandatory Metadata Provider Contact Name Contact Email Landing Page Agency Contact Name Contact Email DOI Additional Information DOI Registration Metadata Requirements

12. ESDIS DOI Registration Process Registration Criteria Earth Science Data Products Products supported by NASA Products generated, archived, or distributed by EOSDIS data centers Collection Level product Long-term usability Challenging Cases 1. Near-real-time products 2. Browse Images 3. NASA-generated NOAA-resident products 4. Products distributed by multiple DAACs 12

13. ESDIS DOI Registration Process 13

14. ESDIS DOIs – Future Direction What did we learn? Where Do We Go From Here? Community Input - Pilot Assessment DOI Format (Structured vs Opaque) Self-registration by DAACs requesting to auto-generated DOIs Landing Page Guidelines Machine-readable Host Options - GCMD/ESDIS/DAACs ESDIS Drivers Automation CMR-compatible DOI Processing 14

15. Future ESDIS DOI System 15

16. Comparison of ESDIS DOI System (Current and Future System) 16 Key FunctionsCurrent SystemFuture System System Information Archive Excel SpreadsheetOracle Database Information Processing ManualAutomatic with Interface to Database Data Review ManualManual/Automatic/on-line DOI Name Uniqueness Verification Automatic/Spreadsh eet Automatic/Database DOI Reserve Manual/SpreadsheetAutomatic/Database DOI Registration ManualAutomatic API/Database DOI Upgrade ManualAutomatic API/Database Reminders Automatic Email /Periodically Reporting On RequestOn-line Interface with ESDIS Systems EMS, CMR

17. Additional Information ESDIS DOI Poster – https://wiki.earthdata.nasa.gov/display/DOIsforEOSDIS ESDIS DOI Public Wiki https://wiki.earthdata.nasa.gov/display/DOIsforEOSDIS/Digital+Obje ct+Identifiers+%28DOIs%29+for+EOSDIS https://wiki.earthdata.nasa.gov/display/DOIsforEOSDIS/Digital+Obje ct+Identifiers+%28DOIs%29+for+EOSDIS 17

18. BACKGROUND SLIDES 18

19. ESDIS DOIs – Current Status 19

20. 20 Provider DOIs Review Information Reserve DOIs with ESDIS Post Information on website/Wiki Register DOIs with EZID Add to ESDIS DOIs Repository Quality Check and Verification Revise DOI Information as updated By EZID and DOI Incomplete Complete Update Update DOIs with EZID ESDIS DOI Registration Workflow Complete but not ready

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22. Member Institute using DataCite: California Digital Library and EZID EZIDEZID is a service providing a way to register and maintain DOI’s in the DOI System. Core functions: Create a persistent identifier: DOI Add/update object location (URL landing page, separate from citation) Add/update citation metadata (DataCite repository, mandatory shown below) Creator (person or organization) Title (long name of dataset) Publisher (holder of the data – organization making it available) Publication Year (year when data was, or will be first available) 22

23. DOI Suffix Syntax – Pilot Phase A DOI consists of two part alphanumeric string: doi:[prefix]/[suffix]. DOI prefix is 10.5067 as assigned by EZID & DataCite for use by ESDIS The suffix is an alphanumeric string; only constraint is that it be unique DOI’s should not contain information that might change over time. DOI Suffix Models include: [mission]/[instrument]/data[m][n] [program]/[measurement group]/data[n] [m] depicts the processing level of the product [n] depicts a sequence number that is assigned on a first-come- first-serve basis. New product versions receive new DOI’s and are assigned a new sequence number. [EOSDIS/DAACname]/unique numeric string [unique-numeric-DAAC identifier]/unique numeric string Examples for Aura 10.5067/Aura/HIRDLS/data[m][n] 10.5067/Aura/MLS/data[m][n] 10.5067/Aura/OMI/data[m][n] 10.5067/Aura/TES/data[m][n] 23

24. Product Landing Page – Pilot Phase Require a unique Web page (section of page) for each product- DOI. The page should have a brief description of the product so that the user knows he/she has reached the right location. The page should have a citation example for the product. Often this is populated in accordance with the DAAC’s metadata, and so may not exactly match the metadata in DataCite – (e.g., for example the title may not have version and shortname). However, it should be as close as possible. The page should provide direct access to the product that the DOI identifies. This means that if a user must go through a search engine to get access to the product, the search entry field should be pre-populated with enough information to uniquely identify the product in the DAAC’s repository (e.g., shortname or title) – so that search results at lease provide the correct product. Spatial and temporal criteria can be required to be entered if they are needed to get reasonable search results. 24

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26. Process for Data Producers to Register DOIs – Pilot Phase Data Producer (PI, IT, SIPS) requests DOIs via email to ESDIS. Presents ESDIS with a list of product titles and target DAAC (the title string is not permanent but will be used to develop the DOI name and so must fairly represent the product). ESDIS develops product spreadsheet with DOI, title, creator, publisher. Publication date and URL Landing page is usually not defined until product is at the DAAC & ready for release. ESDIS presents Data Producer with final ‘reserved’ DOIs Posted with known product metadata on the ESDIS DOI wiki Data Producer imbeds ‘reserved’ DOIs in products and delivers them to the DAAC DAAC prepares landing pages and provides ESDIS with publication data and URLs ESDIS quality checks the DOI metadata, including URL landing page; registers the DOI/metadata in EZID; notifies the DAAC and Provider that the DOIs are active. DAACs must advise ESDIS when URL changes ASAP 26

27. Identifiers in Product Metadata Support multiple kinds of identifiers: Product level – e.g., one identifier per product; all granules have the same DOI; all files have the same DOI. Granule level – e.g., each file has a unique UUID. Embed DOI as global file-level attribute and as EOSDIS core metadata Product Specific Attributes (PSAs) – two places in the product file: Accommodate desire to see DOI using HDF standard tools Support for ECS and ECHO to access DOIs from PSAs Common attribute naming conventions for HDF and netCDF (as much as possible): Use legacy structures for adding identifiers to new versions of existing products Lower case naming convention to accommodate netCDF CF Use ISO 19115 structures for new missions Some identifiers have defined ISO attribute names 27

28. HDF & netCDF Attribute Names Attribute Name distinguishes the kind of identifier: The attribute name: “identifier_product_doi” The attribute value: “10.5067/MEASURES/GSSTF/DATA302” The attribute name: “identifier_file_uuid” The attribute value: “ 599740C3-F062-4F49-A756-8A0DA37BC95B ” Attribute Name Authority defines the authoritative service for use with the identifier Provides the permanent service for resolving DOIs to their URL The attribute name: “identifier_product_doi_authority” The attribute value: “http://dx.doi.org/” Product identifiers can be set in the ECS collection-level metadata through Earth Science Data Type (ESDT) structure (i.e., pre-defined by ECS and then used to ingest products). 28