# EML: Ecological Metadata Language
[](http://github.com/NCEAS/eml)
- **Contributors**: Matthew B. Jones (jones@nceas.ucsb.edu), Chad Berkley (berkley@nceas.ucsb.edu), Jivka Bojilova (bojilova@nceas.ucsb.edu), Dan Higgins (higgins@nceas.ucsb.edu), Chris Jones (cjones@lifesci.ucsb.edu), Corinna Gries (corinna@asu.edu), Peter McCartney (peter.mccartney@asu.edu), James Brunt (jbrunt@lternet.edu), David Blankman (dblankman@lternet.edu), Owen Eddins (oeddins@lternet.edu), Mark Schildhauer (schild@nceas.ucsb.edu), John Harris (harris@nceas.ucsb.edu), Matthew Brooke (brooke@nceas.ucsb.edu), Scott Chapal (scott.chapal@jonesctr.org), Tim Bergsma (tbergsma@kbs.msu.edu), Ken Ramsey (kramsey@jornada.nmsu.edu), Saurabh Garg (sgarg@nceas.ucsb.edu), Margaret O'Brien (mob@msi.ucsb.edu), Mark Servilla (servilla@lternet.edu), James Brunt (brunt@lternet.edu)
- **Version**: 2.1.1
- **Feedback**: [eml-dev@ecoinformatics.org](mailto:eml-dev@ecoinformatics.org)
- **Bug reports**: http://github.com/NCEAS/eml/issues
- **Web site**: http://knb.ecoinformatics.org/software/eml
- **Source code**: http://github.com/NCEAS/eml
- **Validation service**: https://knb.ecoinformatics.org/emlparser/
- **Slack Discussion channel**: #eml on http://slack.nceas.ucsb.edu
- **EML 2.1.1 Specification**
- [Read it online](https://knb.ecoinformatics.org/#external//emlparser/docs/eml-2.1.1/index.html)
- [Download EML](https://knb.ecoinformatics.org/software/dist) - The download consists of the
EML modules, described in the [XML Schema](http://www.w3.org/XML/Schema) language.
In addition, the full documentation on the modules is provided in HTML format.
The Ecological Metadata Language consists of a number of modules that define
an XML markup syntax for ecologically relevant metadata. It was originally
based on work done by the [ESA Committee on the Future of Long-Term
Ecological Data](http://esa.sdsc.edu/FLED/FLED.html) and on a related paper
on ecological metadata by Michener et al. (see Michener, William K., et al., 1997. Ecological Applications, "Nongeospatial metadata for the ecological
sciences" Vol 7(1). pp. 330-342.). Version 1.4 follows that paper closely in
its content implementation, but Version 2 has been modified substantially after
experience using the specification and from feedback from the ecological
community.
This release represents the consensus view of a large number of knowledgeable
scientists and data managers on what metadata are relevant to ecological
data and how best to represent it. Of course, many might differ in opinion
about specific decisions made during the development of EML; we would like to
encourage users to faithfully use the specification in the spirit of
community building. It is better if we all use a metadata language that covers
most of our needs than to modify it and use one that is perfect but not shared
with anybody.
It is notable that some of the rules regarding EML that are important are
expressed only in the EML specification, not in the XML Schema files. This is
because XML Schema was not able to express some of the constraints that we
felt were important to creating a coherent metadata document, particularly
with respect to identifiers and references to identifiers. Thus, we have
included a EML Validity Parser. It checks both EML rules and the schema
rules to be sure an XML document is a valid EML document. It is included
with the release, and provided as an online service. See docs/index.html.
## DOCUMENTATION
Please see the docs/index.html directory for a a list of the relevant
documents pertaining to EML. In particular, this release ships with a full
version of the EML Specification, which is the definitive document explaining
the rules associated with the Ecological Metadata Language.
## FILES
The files in this directory include a "docs" directory that contains the
EML Specification and all documentation for the modules, and an XML Schema
document for each of the modules that make up EML. Also included is a schema
for supporting documentation, and an instance document defining standard
attribute units for EML. The "lib/sample/eml-sample.xml" file is a sample
document illustrating the use of EML. The "test" directory contains a number
of sample instance documents used for testing the schemas, and an application
for checking document validity under JUnit (see http://junit.org).
## RELEASE NOTES
- (see also http://github.com/NCEAS/eml/issues)
### 2.1.1
#### Internationalization in EML 2.1.1
EML 2.1.1 introduces internationalization capabilities that can be used in most
text-based elements. Version 2.1.1 remains backward-compatible with the previous
2.1.0 release. Authors can safely upgrade existing 2.1.0 documents to 2.1.1
without altering any content, though adding additional language translations is
encouraged.
By allowing mixed element content, nested translation elements can be included
without altering or introducing ambiguity with respect to EML element
cardinality. Translation elements use standard xml:lang attributes to specify
the language used for their content. Translation elements can be nested such
that child elements may inherit or override the language used by their
ancestors. The top-level EML element may include an xml:lang attribute which
will apply to every element in the document unless a child element includes a
different xml:lang attribute to override the document default.
Multi-lingual authors of EML should carefully consider their primary target
audience when deciding the default document language. Early adopters should be
aware search tools like Metacat will require custom configuration in order to
search arbitrarily nested translations.
The internationalization feature allows authors to place any language in <value>
tags nested within most EML text fields. The xml:lang attribute should be used
to explicitly declare the language used.
Additional documentation and examples are available in the EML specification.
The i18nNonEmptyStringType is used for simple text, while i18nString for more
structured text elements.
#### Schema changes:
- [76](https://github.com/NCEAS/eml/issues/76): internationalization needed in EML
### 2.1.0 (numbers refer to the corresponding Bugzilla bug id, not the GitHub #)
This release addresses bugs which caused the schema to be invalid with
respect to the W3C specifications using modern validators
(e.g., http://www.w3.org/2001/03/webdata/xsv). Although the changes were minor,
one was incompatible with 2.0 releases, which necessitated the version
number "2.1". In the 2.0 series, the content model for additionalMetadata
included an element <describes> whose cardinality was 0..many, alongside
<xs:any>. This construct is non-deterministic, and so a child element
was added to the additionalMetadata section to contain the <xs:any> content.
Additionally, several elements of txt:TypeText required additional
definition so that mixed content could be accommodated. These errors
were not apparent with validation software available in 2004-2005, but
were brought to light more recently. Several small changes were made to
the enumeration list and unitTypes for standard units and stmml descriptions
of customUnits. Two elements in the literature schema were allowed to be
optional so that articles-in-press could be described. The named type for
element gRing was changed to GRingType.
EML makes use of the STMML schema (stmml.xsd) for describing custom units
and describing its included list of standardUnits (unitList). The STMML
schema was also found to be non-deterministic, and the most reasonable fix
for this bug was not compatible with earlier versions. This error
was NOT related to elements used by EML (unitList or unitType). However,
given that authors of EML instance documents may have made use of other
parts of stmml.xsd, it was decided to the advance the namespace used for
stmml-related files to "stmml-1.1", in keeping with the pattern of version
naming in EML. The stmml authors have been contacted.
- Schema changes:
- 1132: eml.xsd, physical.xsd: fix access rule ambiguities
- 2054: eml.xsd: added the <metadata> tag to additionalMetadata
- 1154: resource.xsd: required element offline has no required children
- 3480: resource.xsd, physical.xsd: nearly duplicate complexTypes, DistributionType and PhysicalDistributionType
- 3165: resource.xsd: provide a place for a url description
- 3227: coverage.xsd: gRing was declared as GRingPointType, is now GRingType
- 1019: coverage.xsd: altitudeUnits should use eml-unitDictionary
- 3500: coverage.xsd: restrict boundingCoordinates to realistic lat/lon ranges
- 1152: attribute.xsd: dateTime elements are named inconsistently; standarized on dateTime
- 2272: attribute.xsd: base types in BoundsGroup changed to xs:float
- 3051: attribute.xsd: missing units were added to enumeration list to match eml-unitDitionary
- 2568: attribute.xsd, entity.xsd: inconsistent naming of methods elements, standardized to <methods>
- 2703: text.xsd: refined element declarations in txt:TextType for para, section; added ulink, citetitle
- 3163: literature.xsd: cardinality of volume and pageRange is now 0..1
- 3164: literature.xsd: literature needs a contact tree
- 3445: stmml.xsd: non-deterministic
- 2083: stmml.xsd: dimension 'current' was wrongly entered as 'charge'
- Parser :
- 3232: EML parser should use full-schema-checking
- 3836: runEMLParser script should include sax-validate
- Stylesheets:
- 3508: create a stylesheet for EML2.0.x to EML 2.1.0
- 3590: eml-documentation stylesheet problem with derived content.
- 2048: param attributeindex defined twice in eml-settings.xsl
- 2085: Access control rules adapted for 2.0.1 and 2.1 (currently not shown)
- 2147: EML Stylesheet problem with web address URL's
- 2226: EML2 style sheet double the number of complex delimited f...
- 3492: the word 'unit' should be pluralized by default
### 2.0.1 (numbers refer to the corresponding Bugzilla bug id, not the GitHub #)
- 249: Update XSLT stylesheets for EML 2.0 modules
- 939: spelling errors for 'its' in index
- 960: parser not correctly parsing <describes> tag in additiona...
- 1008: inline element doesn't support character child
- 1017: documentation error in eml-methods
- 1031: enumeratedDomain doesn't define value order for ordinals
- 1035: Technical documentation on eml-methods has an error
- 1124: update precision field definition and cardinality
- 1129: Change temporalCoverage calendarDate type
- 1132: fix access control rule ambiguities
- 1136: kelvin conversion incorrect in unit dictionary
- 1149: BoundsGroup bounds min & max have incorrect cardinality
- 1150: documentation for KeyTypeCode is wrong
- 1151: misspelled element name
- 1153: dateTimeDomain element should be optional
- 1155: Documentation incorrect for dateTimeDomainType bounds
- 1195: tracking bug for 2.0.1 release
- 1233: dateTime formatString Documentation contains incorrect ex...
- 1529: no tag to specify how to handle mutltiple, repeated delimimeters
- 1652: eml-constraint documentation error
### 2.0.0 - (numbers refer to the corresponding Bugzilla bug id, not the GitHub #)
- 670: DateTimeDomain id/reference validation
- 924: make date time its own measurement scale
- 661: spell check eml-attribute.xsd and synchronize with unitDi
- 918: example tag in eml:documentation
### 2.0.0rc3 (numbers refer to the corresponding Bugzilla bug id, not the GitHub #)
- 471: eml spec overview document
- 624: eml-methods/methodsType needs clarification on choice/seq...
- 627: links broken in EML FAQ
- 629: unit conversion coefficients need checking
- 637: attributeDomain should be required
- 638: request for id/ref in attributeDomain
- 654: scope of the unit element
- 655: need better model for numeric domains for attributes
- 625: Cardinality regarding eml-methods should be corrected in ...
- 626: ProcedureStepType schema needs revision to protect sequen...
- 628: eml-physical has lit: rather than cit: references
- 632: broken link in faq
- 634: Documentation of reference elements in the schemas
- 656: physical should be repeatable
### RC2 (numbers refer to the corresponding Bugzilla bug id, not the GitHub #)
- 568: accommodate of stateful connection information
- 586: resolve validation problem with missing keys
- 588: Remove lineage tags in documentation stylesheets
- 589: eml-coverage: convert element references to types
- 592: fix validation error with xs:anyType
- 594: change cardinality for designDescription and studyAreaDes...
- 596: Proposal: make attribute optional in OtherEntityType.
- 597: In eml-dataTable caseSensitive and orientation are modele...
- 598: literature namespace references are inconsistent
- 599: storageType is repeatable in eml-attribute
- 600: eml-storedProcedure - problems & proposal
- 601: element names in spatial modules do not follow guidelines
- 602: eml-physical fixed textFormat to allow mixed fixed/delimited
- 608: release preparation tasks for EML2.0.0rc2
- 622: redundancy in eml-physical/binaryRaster
### RC1 (numbers refer to the corresponding Bugzilla bug id, not the GitHub #)
- 471: created an EML specification overview document
- 495: created FAQ for EML
- 588: removed lineage tags from documentation stylesheet
- 484: eml-attribute changes to unit and attributeDomain
- 579: fixed eml-docbook validation problems
- 491: eml-coverage changed to correctly import types and to fix singleDateTime model
- 485: eml-physical changed to fix fixed ascii descriptors and distribution
- 477: complexTypes imports changed to consistent model
- 486: fixed spelling errors in eml-constraint
- 492: eml-literature changed for EndNote consistency
- 496: copyright updated throughout
- 557: textual elements changed to use docbook subset define in eml-text.xsd
- 563: changed id types from xs:ID to xs:string to allow numeric ids
- 482: eml-dataset changed to include method element
- 489: eml-protocol completely revised based on feedback, eml-method.xsd created
- 544: eml-attribute storageType and attributeDomain documentation clarified
- 556: format of eml namespaces changed to include ecoinformatics.org
- 539: added additionalInfo and alternateIdentifier to eml-dataTable.xsd
- 568: redesigned DistributionType to allow richer connection descriptions
- 566: changed imports in eml-resource to import resource types not elements
- 567: created eml sample documents and XML validation framework using ant/junit
### Beta9 Fixes-
1. Changed packaging concept to use internal id and references instead
of triples
2. Review and revised all modules according to agreed upon changes from
the April, 2002 EML meeting at Sevilleta Field Station
### Beta 8 Fixes-
1. Fixed illegal declaration of type and extension in eml-entity
2. Updated all PNG image files
### Beta 7 Fixes-
1. Added a 'style' subdirectory with a style sheet for most modules
. to translate the metadata to HTML
2. Changed names of coverage elements to be human readable
3. Updated the namespaces to reflect the current version number of EML
4. Added an eml-data module for the in-lining of data.
5. Added the eml module for creating packages all in one file. It is a single
node with a model of ANY so any of the eml modules can be put into it.
6. Numerous bug fixes (see bugzilla.ecoinformatics.org)
## Copyright and License
Copyright: 1997-2017 Regents of the University of California,
University of New Mexico, and
Arizona State University
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
## Funding and Acknowledgements
This material is based upon work supported by the National Science Foundation
under Grant No. 0225676, DEB-9980154, DBI-9904777, DEB-0072909, DBI-9983132,
and DEB-9634135. Any opinions, findings and conclusions or recommendations
expressed in this material are those of the author(s) and do not necessarily
reflect the views of the National Science Foundation (NSF).
This product includes software developed by the Apache Software
Foundation (http://www.apache.org/). See the LICENSE file in lib/apache
for details.
The source code, object code, and documentation in the com.oreilly.servlet
package is copyright and owned by Jason Hunter. See the cos-license.html file
for details of the license. Licensor retains title to and ownership of the
Software and all enhancements, modifications, and updates to the Software.
This product includes software developed by the JDOM Project
(http://www.jdom.org/). See jdom-LICENSE.txt for details.