1. and Transmission Standard overview – and case study
Metadata Encoding
and Transmission Standard
overview – and case study
Markus Enders, SUB Göttingen

2. METS overview METS was derived from „Making of America“ format
--> generalize format; usage for other media types
Funded by Digital Library Federation (DLF)
multiple structures are possible; type attribute can be "logical, physical" etc...
nested div elements
Editorial Board is steering the development
helds “Mets Opening Days”

3. METS overview structMap central object mandatory
<mets:div TYPE=”Monograph” LABEL=”From Hamburg to San Fransisco” ORDER=”1” ID="DMD1">
structMap
<div>
central object
mandatory
nested <div> store structure
multiple structures (type attribute)
multiple structures are possible; type attribute can be "logical, physical" etc...
nested div elements

4. METS overview structLink structMap central object mandatory
<mets:structLink>
<mets:smLink xlink:from=”div1”
xlink:to=”div2”>
structLink
structMap
<div>
central object
mandatory
nested <div> store structure
multiple structures (type attribute)
structLink: stores links between two <div> elements
link between two div elements from
different <structMap>

5. METS overview contains file groups structLink structMap (nested)
files are contained
in file groups
basic technical
metadata as
attributes
link from a <div> to
one or more files
structLink
structMap
<div>
<fptr>:
FileSec
parallel or sequential
file groups can be nested;
Files are always contained in file Groups.
files: attributes for checksums, size, mime type – further technical metadata can be stored in metadata section
<fptr> = file pointer
<par> or <seq>: several file pointers for each <div> possible; files can be parallel or sequential
can link into a file:
-- images: HTML coordinates
-- byte-offsets
-- XML IDs
-- time codes (streaming media)
link to streams
<FileGrp>
<file>
link into
a file

6. METS overview Descriptive metadata vs. Administrative Metadata
metadata can be embedded or
referenced
XML or binary metadata
extensions schemas used:
MODS, DC, premis etc...
m:n relationship between
metadata and <div> od <file>
Desc. MD
extension schema
Admin. MD
Administrative Metadata: seperate sections: technical metadata, digital provenance metadata, rights metadata, source metadata
METS does not come with an own metadata schema, but enables to plug in different extensions schemas
extension schema
techMD
digiProvMD
rightsMD
sourceMD

7. METS overview structLink StructMap Desc. MD FileSec Admin. MD
<div>
extension schema
FileSec
Admin. MD
several metadata sections for each <div> or <file> possible
a single metadata section can be used by several <div> or <file> objects
<FileGrp>
extension schema
<file>
techMD
digiProvMD
rightsMD
sourceMD

8. METS overview METS Header structLink StructMap Desc. MD FileSec
<div>
extension schema
FileSec
Admin. MD
METS header contains information about the METS object (mets file), NOT about the content
<FileGrp>
extension schema
<file>
techMD
digiProvMD
rightsMD
sourceMD

9. METS overview How does the linking work (in XML): XML IDs are used:
each target must have a unique ID
<mets:dmdSec ID="DMD1">
Metadata:
DMDID and ADMID are of the type IDREFs
<mets:div DMDID="DMD1 DMD2">
ID need only locally unique (within the same file)
IDREFS: space separated
pointers may point everywhere in the file: even from DMDID to <file>: file will validate
Not a problem of METS data model but of XML representation
File pointer:
<mets:fptr FILEID="FN10081"/>

10. METS example (1) Digitization Centre
Simple Document model (single structure)
several content files per document
(single TIFF image per page)
bibliographic metadata
logical structure for the document
(table fo content)
direct relationships between logical structure
entities and content files
This model was developed in mid 90ies, stored in XML with a proprietary metadata set

11. METS example (1) Digitization Centre Simple logical document model
Logical structure
<structMap>
Content files
<fileSec>
Monograph
tif
tif
Chapter
tif
Chapter
tif
tif
Max. eine Datei pro Seite; Namenskonvention bestimmt die Reihenfolge
Chapter
tif
Chapter
tif
Chapter
tif

12. METS example (1) Digitization Centre Simple logical document model
Logical structure
<structMap>
Content files
<fileSec>
Metadaten
Monograph
Metadaten
tif
tif
Chapter
tif
Chapter
tif
tif
file can belong to several document structure entities
Chapter
tif
Chapter
tif
Chapter
tif

13. METS example (1) Digitization Centre Simple logical document model
Logical structure
<METS:structMap TYPE="LOGICAL">
<METS:div TYPE="Monograph"DMDID="dmdlog0001">
<METS:div TYPE="TitlePage" ID="log0002">
<METS:fptr FILEID="bitonal0001"/>
</METS:div>
<METS:div TYPE="Dedication" ID="log0003"/>
<METS:fptr FILEID="bitonal0002"/>
......
</METS:structMap>
file can belong to several document structure entities

14. METS example (1) Digitization Centre Simple logical document model
Metadata
<METS:dmdSec ID="dmdlog0001">
<METS:mdWrap MDTYPE="MODS">
<METS:xmlData>
<MODS:mods>
......
</MODS:mods>
</METS:xmlData>
</METS:mdWrap>
</METS:dmdSec>
MODS metadata embedded in METS

15. METS example (1) Digitization Centre Simple logical document model
ContentFiles
<METS:fileSec>
<METS:fileGrp>
<METS:file ID="bitonal0001" MIMETYPE="image/tiff">
<METS:FLocat LOCTYPE="URL"
xlink:href="file://./ tif"/>
</METS:file>
</METS:fileGrp>
</METS:fileSec>
Files are only referenced
no metadata section for files; basic technical metadata is included as attributes:
size, mimetype and checksum...

16. METS example (2) Digitization Centre
Document model with two structures
logical structure (TOC)
physical structure (bound book, page)
realtionships between structures
Every structure entity has its own metadata
section
content files are linked to physical structure
entities

17. METS example (2) Digitization Centre
Document model with two structures
Logical structure
Phys. structure
Content files
Monograph
Bound Book
tif
Page
tif
Chapter
Page
tif
Chapter
Page
tif
Page
tif
page area: column
Chapter
page area
tif
Chapter
Page
tif
Chapter
Page
tif
Page
HiRes01.jpg
Page
Fulltext.xml

18. METS example (2) Digitization Centre
Document model with two structures
Map two structures
<METS:structMap TYPE="LOGICAL">
<METS:div TYPE="Monograph" ID="log0001"
DMDID="dmdlog0001"/>
</METS:structMap>
<METS:structMap TYPE="PHYSICAL">
<METS:div TYPE="BoundBook" ID="phys0001"
DMDID="dmdphys0001">
<METS:div TYPE="page" ID="phys0002"
DMDID="dmdphys0002"/>
</METS:div>
</METS:structMap>

19. METS example (2) Digitization Centre
Document model with two structures
Map two structures
<METS:structLink TYPE="xxx">
<!--Monograph -->
<METS:smLink from="log0001" to="phys0001"/>
<!—title page-->
<METS:smLink from="log0002" to="phys0002"/>
</METS:structLink>
link from logical to physical (pages)

20. METS example (2) Digitization Centre
Document model with two structures
Link to several files
<METS:div TYPE="page" ID="phys0002" DMDID="dmdphys0002">
<METS:fptr FILEID="bitonal0001"/>
<METS:fptr FILEID="hires0001"/>
</METS:div>
Link to page area
files are neither sequential nor parallel, but alternative versions
link to page area: COORDS attribute contains information where the column is
<METS:div TYPE="column" ID="phys0003" DMDID="dmdphys0002">
<METS:fptr>
<METS:area FILEID="bitonal "
COORDS="40x40x150x250"/>
</METS:fptr>
</METS:div>

21. METS example (2) Digitization Centre
Document model with two structures
Logical structure
Phys. structure
Content files
Monograph
Bound Book
tif
Page
tif
Chapter
Page
tif
Chapter
Page
tif
Page
tif
Link to full text: single fulltext file (TEI) for the whole monograph
Chapter
page area
tif
Chapter
Page
tif
Chapter
Page
tif
Page
HiRes01.jpg
Page
Fulltext.xml

22. METS example (2) Digitization Centre
Document model with two structures
Link to fulltext (TEI):
<METS:div TYPE="page">
<METS:fptr>
<METS:area FILEID="teixml01" BEGIN="xx02"
END"xx02"BETYPE="IDREF"/>
</METS:fptr>
</METS:div>
<METS:div TYPE="page">
<METS:fptr>
<METS:area FILEID="teixml01" BEGIN="xx02"
END"xx02"BETYPE="IDREF"/>
</METS:fptr>
</METS:div>
files are neither sequential nor parallel, but alternative versions
link to page area: COORDS attribute contains information where the column is
<TEI:p>
<TEI:q id="xx01">....</TEI:q>
<TEI:q id="xx02">....</TEI:q>
<TEI:pb n="13"/>
<TEI:q id="xx03">...</TEI:q>
</TEI:p>

23. METS example (2) Digitization Centre
Document model with two structures
Fulltext is referenced, not embedded in METS file
due to file sizes.
METS file is about 2 – 3 MB
fulltext is about 20 MB
Use MODS for descriptive metadata for
logical structure entities
files are neither sequential nor parallel, but alternative versions
link to page area: COORDS attribute contains information where the column is
Own descriptive metadata schema for physical
structure entites – storing page numbers

24. METS example (2) Digitization Centre Why did the GDZ choose METS:
easily extendable: may start with image digitization and may add fulltext later
complex structure needs to be stored
Fulltext format not flexible enough:
(1) TEI knows only one kind of structure
(logical); does not know any pages (just page
breaks).
(2) no extensive metadata model
--> fulltext files needs to be linked to a METS file

25. METS creation:
By hand in XML editor (structMap the only required object)
special tools for certain purposes, e.g:
- conversion tools for web-archiving
- ...
At GDZ: GOOBI workflow management tool
to do: General METS API, which implements the data model.

26. METS presentation: Depends on your METS file:
- simple XSLT transformations
- repository systems (ContentDM, Fedora etc.)
- some page turners available
(for digitized content)

27. METS-Profile Documentation Documentation is necessary:
Describe objects and relationships in you document model:
What objects are available
What metadata are attached to those objects
How are objects related to each other (trees)
How to store unambiguous order?
Are there non-hierarical relationships between objects?
Which content files are available? How's the access granularity?

28. METS-Profile Documentation
Documentation should not describe a format generally, but the precise usage of a packaging format.
Example:
How to inheirit relationships between two structure-trees?
Chapter
Page
Page
Need the column be linked to the chapter directly or is an indirect link sufficient?
Page
Column

29. METS-Profile Documentation
Documentation should not describe a format generally, but the precise usage of a packaging format.
Examples:
How to link into fulltext files? Usage of BEGIN and END attributes
How to store the order of <div> elements?
What kind of <div> elements are available?
Developing and sharing documentation encourages the usage of „complex document formats“ even for simple documents.
 documents can be enriched with additional information later on.

30. METS-Profile Documentation
METS Profile describes the usage of METS for a special scenario:
- what extension schemas are used?
- what authority files?
- usage of attributes and elements
METS-profile schema available; profile is an XML file, which is not machine readable.
„registry“ on METS website available
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