Referring to elements within METS
| METS makes extensive provisions for using attributes of the [[Referring to Parts of XML Documents | ID, IDREF and IDREFS datatypes]] to create cross-references between related elements. Ultimately, these provisions allow units of information appearing in dispersed locations across a METS instance document to be linked to all of their appropriate contexts without redundancy. METS elements of the mdType and fileType datatypes have required ID attributes which allow the metadata and content file elements that implement these datatypes to be referenced from the other parts of the METS instance document to which they pertain. In addition to this, <div> elements in the <structMap> and many other elements can include ID attribute values that allow them to be referenced by other elements. METS’ specific cross-referencing provisions for different contexts follow. |
Context 1: <md> metadata
- A unique ID attribute value must identify each
<md>element in a METS instance document. - Each of the following elements can reference one or more specific
<md>elements by citing their ID values in its MDID attribute (the MDID attribute is of IDREFS type):
In the example below the ID attribute value of “MD1” identifies the single <md> element. The root <div> in the <structMap> references this <md> by means of its MDID attribute. Thus the encoding indicates that the descriptive metadata in the <md> identified by the ID value “MD1” applies to the entire content as represented by the root <div> in the <structMap>.
<mets:mets
xmlns:mets="http://www.loc.gov/METS/v2" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.loc.gov/METS/v2 https://github.com/mets/METS-schema/raw/mets2/v2/mets.xsd http://www.loc.gov/mods/v3 http://www.loc.gov/mods/v3/mods-3-1.xsd"
OBJID="ark:/13030/kt9s2009hz" LABEL="Martial Epigrams">
<mets:mdSec>
<mets:md ID="MD1">
<mets:mdWrap MDTYPE="MODS">
<mets:xmlData>
<mods:mods>
<mods:titleInfo>
<mods:title>Martial Epigrams</mods:title>
</mods:titleInfo>
</mods:mods>
</mets:xmlData>
</mets:mdWrap>
</mets:md>
</mets:mdSec>
<mets:structSec>
<mets:structMap TYPE="physical">
<mets:div TYPE="book" LABEL="Martial Epigrams II" MDID="MD1"/>
</mets:structMap>
</mets:structSec>
</mets:mets>
Example 2: Administrative metadata
In the example below the ID attribute value of “App4ADM1” identifies the first <md> element and the ID value “App4ADM2” identifies the second <md> element. The MDID attribute on the single <file> element in the <fileSec> references both of these ID values (“App4ADM1 App4ADM2”). Thus the encoding indicates that both the technical metadata in the first <md> element identified by the ID value “App4ADM1” and the rights metadata in the second <md> element identified by the ID value “App4ADM2” apply to the content file represented by the <file> element.
<mets:mets xmlns:mets="http://www.loc.gov/METS/v2" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:rts="http://cosimo.stanford.edu/sdr/metsrights/" xmlns:mix="http://www.loc.gov/mix/v20"
xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.loc.gov/METS/v2 https://github.com/mets/METS-schema/raw/mets2/v2/mets.xsd
http://cosimo.stanford.edu/sdr/metsrights/ https://www.loc.gov/standards/rights/METSRights.xsd
http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-1.xsd
http://www.loc.gov/mix/v20 http://www.loc.gov/standards/mix/mix.xsd"
OBJID="ark:/13030/hb3c6005tv" TYPE="still image" LABEL="S. P. [Simmon Peña] Storms, Interpreter [&c], Indian agency - near Grass Valley, California, 1851"
PROFILE="http://www.loc.gov/standards/mets/profiles/0000000X.xml">
<mets:mdSec>
<mets:md ID="App4ADM1">
<mets:mdWrap MDTYPE="NISOIMG">
<mets:xmlData>
<mix:mix>
<mix:BasicImageParameters>
<mix:Format>
<mix:MIMEType>image/tiff</mix:MIMEType>
<mix:Compression>
<mix:CompressionScheme>1</mix:CompressionScheme>
</mix:Compression>
<mix:PhotometricInterpretation>
<mix:ColorSpace>2</mix:ColorSpace>
<mix:ICCProfile>
<mix:ProfileName>DilE836G18_01</mix:ProfileName>
</mix:ICCProfile>
</mix:PhotometricInterpretation>
</mix:Format>
</mix:BasicImageParameters>
<mix:ImageCreation>
<mix:ImageProducer>DIL/U.C. Berkeley Library </mix:ImageProducer>
<mix:DeviceSource>reflection print scanner </mix:DeviceSource>
<mix:ScanningSystemCapture>
<mix:ScanningSystemHardware>
<mix:ScannerManufacturer>Epson </mix:ScannerManufacturer>
<mix:ScannerModel>
<mix:ScannerModelName>836xl </mix:ScannerModelName>
<mix:ScannerModelSerialNo>B05401003MG9601009 </mix:ScannerModelSerialNo>
</mix:ScannerModel>
</mix:ScanningSystemHardware>
</mix:ScanningSystemCapture>
</mix:ImageCreation>
<mix:ImagingPerformanceAssessment>
<mix:SpatialMetrics>
<mix:SamplingFrequencyUnit>2</mix:SamplingFrequencyUnit>
<mix:XSamplingFrequency>600</mix:XSamplingFrequency>
<mix:YSamplingFrequency>600</mix:YSamplingFrequency>
</mix:SpatialMetrics>
<mix:Energetics>
<mix:BitsPerSample>8,8,8</mix:BitsPerSample>
<mix:SamplesPerPixel>3</mix:SamplesPerPixel>
</mix:Energetics>
</mix:ImagingPerformanceAssessment>
</mix:mix>
</mets:xmlData>
</mets:mdWrap>
</mets:md>
<mets:md ID="App4ADM2">
<mets:mdWrap MDTYPE="METSRights">
<mets:xmlData>
<rts:RightsDeclarationMD RIGHTSCATEGORY="OTHER" OTHERCATEGORYTYPE="UNKNOWN">
<rts:RightsHolder>
<rts:RightsHolderComments>All requests to reproduce, publish, quote from, or otherwise use collection materials must be submitted in writing to the Head of Access Services,
The Bancroft Library, University of California, Berkeley 94720-6000. Consent is given on behalf of The Bancroft Library as the owner of the physical items and does not
constitute permission from the copyright owner. Such permission must be obtained from the copyright owner. See: http:// bancroft.berkeley.edu/reference/
permissions.html </rts:RightsHolderComments>
</rts:RightsHolder>
<rts:Context CONTEXTCLASS="GENERAL PUBLIC">
<rts:Constraints>
<rts:ConstraintDescription>Copyright status unknown. Some materials in these collections may be protected by the U.S. Copyright Law (Title 17, U.X.C.). In addition, the
reproduction of some materials may be restricted by terms of University of California gift or purchase agreements, donor restrictions, privacy and publicity rights,
licensing and trademarks. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of
copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests
exclusively with the user. </rts:ConstraintDescription>
</rts:Constraints>
</rts:Context>
</rts:RightsDeclarationMD>
</mets:xmlData>
</mets:mdWrap>
</mets:md>
</mets:mdSec>
<mets:fileSec>
<mets:fileGrp VERSDATE="2003-01-22T00:00:00.0" USE="archive image">
<mets:file ID="App4FID1" MIMETYPE="image/tiff" SEQ="1" CREATED="2003-01-22T00:00:00.0" MDID="App4ADM1 App4ADM2" GROUPID="GID1">
<mets:FLocat LOCREF="http://offlineimage/calcultures/ucb/cubanc_1_2_00004722a.tif" LOCTYPE="URL"/>
</mets:file>
</mets:fileGrp>
</mets:fileSec>
<mets:structSec>
<mets:structMap TYPE="physical">
<mets:div ORDER="1" TYPE="still image" LABEL="S. P. [Simmon Peña]
Storms, Interpreter [&c], Indian agency - near Grass Valley,
California, 1851">
<mets:fptr FILEID="App4FID1"/>
</mets:div>
</mets:structMap>
</mets:structSec>
</mets:mets>
Context 2: <file> content files
- A unique ID attribute value must identify each
<file>element in the<fileSec>of a METS document. - Each of the following elements can reference the specific
<file>pertinent to it by citing the<file>element’s ID value in its FILEID attribute. (The FILEID attribute is of type IDREF).- mets/structMap/div/fptr
- mets/structMap/div/fptr/area
- mets/structMap/div/fptr/seq/area
- mets/structMap/div/fptr/par/area
- mets/structMap/div/fptr/par/seq/area
Example
The Example 2 of the previous usage context immediately above also demonstrates the current context. In that example, the ID attribute value of “App4FID1” identifies the single
<file>element. The single<fptr>element under the root<div>of the<structMap>references this ID value. Thus the encoding indicates that the content file represented by the<file>element with an ID value of “App4FID1” manifests the root<div>element.