This document highlights changes and new features in EML 2.2. EML authors should also refer to the affected sections in the normative schema documents for complete usage information and examples.
EML 2.2 is backward compatible, i.e., EML 2.0 and 2.1 documents could be relabled as EML 2.2 without violating the schema. However, some predefined values, particularly units, are deprecated in favor of new values to fix mispellings or inconsistencies. EML authors are encouraged to migrate away from deprecated values.
EML MAINTAINERS: Is this in the works??????
Existing EML 2.1-series documents can be converted to EML 2.2.0 using the XSL stylesheet that accompanies this release, as described in section 2 below.
See the 'Readme' that accompanies the distribution for a complete list of the bugs addressed, and for information of interest to developers.
Q: Unit Additions and Changes
A: Many units were added for EML 2.2.0, including units supporting oceanography, climatology, forestry and limnology. The following unit types from the unit dictionary have been renamed to better reflect their dimensionality:
- massFlux is now massRate
- arealMassDensityRate is now massFlux
- amountOfSubstanceWeightFlux is now amountOfSubstanceWeightRate
Dozens of units are now deprecated in favor other units to address issues such as naming consistency. Use the "deprecatedInFavorOf" attribute in eml-unitDictionary.xml to identify deprecated units.
Q: BibTeX Support
A: CitationType elements can use the new <bibtex> element as an alternative to encoding citations in the EML XML structures. BibTeX entries generally play well inside of XML structures, but XML escaping is still needed for special characters, so consider embedding BibTeX entries in CDATA blocks if XML escaping becomes cumbersome.
<citation>
<bibtex>
@article{fegraus_2005,
title = {Maximizing the {Value} of {Ecological} {Data} with {Structured} {Metadata}: {An} {Introduction} to {Ecological} {Metadata} {Language} ({EML}) and {Principles} for {Metadata} {Creation}},
journal = {Bulletin of the Ecological Society of America},
author = {Fegraus, Eric H. and Andelman, Sandy and Jones, Matthew B. and Schildhauer, Mark},
year = {2005},
pages = {158--168}
}
</bibtex>
</citation>Q: Citation Lists
A: EML 2.2.0 includes a new <literatureCited> element as a CitationListType that represents one or more citations. These citations can be a series of <citation> elements or a <bibtex> element with a list of citations.
Example of <literatureCited> element in EML 2.2.0:
<literatureCited>
<citation>
<bibtex>
@article{fegraus_2005,
title = {Maximizing the {Value} of {Ecological} {Data} with {Structured} {Metadata}: {An} {Introduction} to {Ecological} {Metadata} {Language} ({EML}) and {Principles} for {Metadata} {Creation}},
journal = {Bulletin of the Ecological Society of America},
author = {Fegraus, Eric H. and Andelman, Sandy and Jones, Matthew B. and Schildhauer, Mark},
year = {2005},
pages = {158--168}
}
</bibtex>
</citation>
<citation>
<title>Title of a paper that this dataset, or its metadata, references.</title>
<creator>
<individualName>
<givenName>Mark</givenName>
<surName>Jarkady</surName>
</individualName>
</creator>
<pubDate>2017</pubDate>
<article>
<journal>EcoSphere</journal>
<publicationPlace>https://doi.org/10.1002/ecs2.2166</publicationPlace>
</article>
</citation>
<bibtex>
@article{hampton_2017,
title = {Skills and {Knowledge} for {Data}-{Intensive} {Environmental} {Research}},
volume = {67},
copyright = {All rights reserved},
issn = {0006-3568, 1525-3244},
url = {https://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/bix025},
doi = {10.1093/biosci/bix025},
language = {en},
number = {6},
urldate = {2018-02-15},
journal = {BioScience},
author = {Hampton, Stephanie E. and Jones, Matthew B. and Wasser, Leah A. and Schildhauer, Mark P. and Supp, Sarah R. and Brun, Julien and Hernandez, Rebecca R. and Boettiger, Carl and Collins, Scott L. and Gross, Louis J. and Fernández, Denny S. and Budden, Amber and White, Ethan P. and Teal, Tracy K. and Labou, Stephanie G. and Aukema, Juliann E.},
month = jun,
year = {2017},
pages = {546--557}
}
@article{collins_2018,
title = {Temporal heterogeneity increases with spatial heterogeneity in ecological communities},
volume = {99},
copyright = {All rights reserved},
issn = {00129658},
url = {http://doi.wiley.com/10.1002/ecy.2154},
doi = {10.1002/ecy.2154},
language = {en},
number = {4},
urldate = {2018-04-16},
journal = {Ecology},
author = {Collins, Scott L. and Avolio, Meghan L. and Gries, Corinna and Hallett, Lauren M. and Koerner, Sally E. and La Pierre, Kimberly J. and Rypel, Andrew L. and Sokol, Eric R. and Fey, Samuel B. and Flynn, Dan F. B. and Jones, Sydney K. and Ladwig, Laura M. and Ripplinger, Julie and Jones, Matt B.},
month = apr,
year = {2018},
pages = {858--865}
}
</bibtex>
</literatureCited>Q: Markdown Support
A: TextType elements can include GitHub Flavored Markdown using the new <markdown> element. See the description for the <markdown> element in eml-text.xsd for more details on embedded images, inline citations, and formatting considerations regarding special characters and indentation.
Example of markdown in EML 2.2.0:
<markdown>
An introduction goes here.
It can include multiple paragraphs. And these paragraphs should have enough text to wrap in a wide browser. So, repeat that last thought. And these paragraphs should have enough text to wrap in a wide browser. So, repeat that last thought.
Text can cite other works, such as [@jones_2001], in which case the
associated key must be present as either the citation identifier in a
`bibtex` element in the EML document, or as the `id` attribute on one of the
`citation` elements in the EML document. These identifiers must be unique
across the document.
And bulleted lists are also supported:
- Science
- Engineering
- Math
It can also include equations:
$$\left( x + a \right)^{n} = \sum_{k = 0}^{n}{\left( \frac{n}{k} \right)x^{k}a^{n - k}}$$
Plus, it can include all of the other features of [Github Flavored Markdown (GFM)](https://github.github.com/gfm/).
</markdown>Q: Usage Citations
A: EML 2.2.0 documents can include a non-comprehensive list of citations in which the data were explicitly used via a <usageCitation> element, which is a CitationType.
Example usageCitation element:
<dataset>
...
<usageCitation>
<bibtex>
@article{jones_2001,
title = {Managing scientific metadata},
volume = {5},
issn = {10897801},
url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=957896},
doi = {10.1109/4236.957896},
number = {5},
journal = {IEEE Internet Computing},
author = {Jones, Matthew B. and Berkley, Chad and Bojilova, Jivka and Schildhauer, Mark},
year = {2001},
pages = {59--68}
}
</bibtex>
</usageCitation>
...
</dataset>Q: Reference Publications
A: For cases when a research paper illustrates the usage of a dataset, the new <referencePublication> element can be used to associate the dataset with the paper.
<dataset>
...
<referencePublication>
<bibtex>
@article{ludwig_2018,
title = {Permafrost carbon and nitrogen, Yukon-Kuskokwim Delta, Alaska},
url = {http://ecosphere.esa.org/article/yyyy.zzzzzzz},
doi = {10.xxxx/yyyy.zzzzzz},
journal = {EcoSphere},
author = {Ludwig, Sarah},
year = {2018}
}
</bibtex>
</referencePublication>
...
</dataset>Q: Data Paper Support
A: ESA and other societies are moving towards the publication of data papers that include more complete narratives about a data set and its importance and use. To support data papers, EML 2.2.0 includes new optional fields for Introduction, Getting Started, and Acknowledgements, as well as markdown and citation-related elements described elsewhere in this document.
See the example EML document for a data paper.
Q: Dataset license
A: Datasets can now include a <licensed> element along with a URL to a license.
<dataset>
...
<licensed>
<licenseName>Creative Commons Attribution 4.0 International</licenseName>
<url>https://spdx.org/licenses/CC-BY-4.0.html</url>
<identifier>CC-BY-4.0</identifier>
</licensed>
...
</dataset>Q: Structured Funding Information
A: EML 2.2.0 sees the addition of an <award> element to support structured funding information for a research project. This is used as an alternative or in addition to the <funding> element which is a text type.
<project>
...
<funding><para>Funding is from a grant from the National Science Foundation.</para></funding>
<award>
<funderName>National Science Foundation</funderName>
<funderIdentifier>https://doi.org/10.13039/00000001</funderIdentifier>
<awardNumber>1546024</awardNumber>
<title>Scientia Arctica: A Knowledge Archive for Discovery and Reproducible Science in the Arctic</title>
<awardUrl>https://www.nsf.gov/awardsearch/showAward?AWD_ID=1546024</awardUrl>
</award>
</project>Q: "unkown" deprecated as <maintenanceUpdateFrequency> element value.
A: Some EML documents have specified "unkown" instead of "unknown" for the maintenanceUpdateFrequency because there is a typo in the list of allowed values in eml-dataset.xsd. For EML 2.2.0, a value of "unknown" is added to the list, while the the original value of "unkown" is kept in the enumeration for backwards compatibility with a note that its use is deprecated.
Q: Accommodating Semantic Metadata
A: EML 2.2.0 supports entering terms from an ontology via <annotation> elements to further describe items such as data attributes, entity groups, and resource groups. Annotations are allowed in five locations in the EML document:
- in
attribute,entity, anddataset(or other resource) elements - in an
/eml/annotationsroot element - in
/eml/additionalMetadata
When the annotation is embedded in a containing EML attribute element, the annotation's subject is that attribute:
<attribute id="att.12">
<attributeName>biomass</attributeName>
...
<annotation>
<propertyURI label="of characteristic">http://ecoinformatics.org/oboe/oboe.1.2/oboe-core.owl#ofCharacteristic</propertyURI>
<valueURI label="Mass">http://ecoinformatics.org/oboe/oboe.1.2/oboe-characteristics.owl#Mass</valueURI>
</annotation>
<annotation>
<propertyURI label="of entity">http://ecoinformatics.org/oboe/oboe.1.2/oboe-core.owl#ofEntity</propertyURI>
<valueURI label="Plant Sample">http://example.com/example-vocab-1.owl#PlantSample</valueURI>
</annotation>
</attribute>For annotations in /eml/annotations, the subject of the annotation is
established using a references attribute that points at the id of the subject of
the annotation:
<annotations>
<annotation references="CDR-biodiv-table">
<propertyURI label="Subject">http://purl.org/dc/elements/1.1/subject</propertyURI>
<valueURI label="grassland biome">http://purl.obolibrary.org/obo/ENVO_01000177</valueURI>
</annotation>
</annotations>For annotations in /eml/additionalMetadata, the subject is the element with
the id listed within the associated <describes> element:
<additionalMetadata>
<describes>adam.shepherd</describes>
<metadata>
<annotation>
<propertyURI label="member of">https://schema.org/memberOf</propertyURI>
<valueURI label="BCO-DMO">https://doi.org/10.17616/R37P4C</valueURI>
</annotation>
</metadata>
</additionalMetadata>Q: Support for ids in <taxonomicClassification> element
A: <taxonomicClassification> elements can now include a reference to external identifiers, e.g., to a code from a system like ITIS or WoRMS.
<taxonomicClassification id="taxon_MAPY">
<taxonRankName>species</taxonRankName>
<taxonRankValue>Macrocystis pyrifera</taxonRankValue>
<commonName>Giant Kelp</commonName>
<taxonId provider="ITIS">11274</taxonId>
<taxonId provider="https://www.ncbi.nlm.nih.gov/taxonomy">35122</taxonId>
</taxonomicClassification>Q: How can I convert from earlier versions of EML?
A: An XSL stylesheet is provided with the EML Utilities to convert valid EML 2.1-series documents to EML 2.2.0 (see http://knb.ecoinformatics.org/software/eml/). The stylesheet performs basic tasks to create a template EML 2.2.0 document. For more information, see the Utilities documentation.
Q: Validity of new EML 2.2.0 documents
A: Because of the flexibility allowed in EML, the stylesheet may encounter EML 2.1.0/1 structures that cannot be transformed or that may result in invalid EML 2.2.0 after processing. For example, by design <additionalMetadata> sections are parsed laxly, and so it is possible for their content in EML-2.1.0/1 to contain <access> trees which are invalid. Document authors are advised to check the validity of their new EML 2.2.0 after transformation. EML instance documents can be validated in these ways:
-
With the online EML Parser. The online parser will validate all versions of EML.
-
Using the Parser that comes with EML. To execute it, change into the 'lib' directory of the EML release and run the 'runEMLParser' script passing your EML instance file as a parameter. The script performs two actions: it checks the validity of references and id attributes, and it validates the document against the EML 2.2 schema. The EML parser included with the distribution is capable of checking only EML 2.2.0 documents, and cannot be used to validate earlier versions (e.g., EML 2.1.1).
-
If you are planning to contribute your EML 2.2.0 document to a Metacat repository, note that the Metacat servlet checks all versions of incoming EML for validity as part of the insertion process.