# Presentation: 216426

## METS Dissemination: Interfaces

- METS Opening Day
- 28 October, 2003
- Leslie Myrick

## NYU Collections using METS Interfaces

- EAD Finding Aids
- Tokyo Tribunal Proceedings
- Afghanistan Digital Library *
- CRL Web Archiving Project
- DRAM
- Hemispheric Institute
- REPO History Sign Project

## Ingredients

- Tomcat Servlet Engine
- XSLServlet or SaxonServlet
- XT or Saxon Transformation Engine
- MySQL Database for generation
- Perl DBI and CGI for interface to DB

## Why XSLT? 

- Relatively simple
- Open-source, platform-neutral, standards-based
- Official Recommendation of W3C
- It is XML

## Free XSLT Tools Abound

- Editors: emacs, NoteTab + Xalan .bat
- Servlet Containers – Tomcat, Resin
- Transformation Engines – Xalan, Saxon, XT
- Parsers – Xerces, Aelfred,XP/Sax, Crimson
- Parsing APIs: DOM, SAX

## METS as a Functional Syntax

- METS designed not only for transfer and archival management, but for giving access to, navigating an object
- METS + XSLT can create dynamic interfaces with links to resources and their metadata
- METS can be dumped into Oracle, indexed and searched using context-aware queries.

## How to Navigate a METS Document

- ID, IDREF, IDREFS
- Each ID must have a matching IDREF and v.v.
- To match an ID against more than one value use IDREFS (e.g. multiple ADMID values in METS:file
- Keys
- More flexible; they make document into a database

## ID, IDREF, IDREFS

- Provide navigable relationships between files and their metadata in complex Schema e.g. METS
- Must be defined in Schema or DTD
- Restrictive: Element can have only one ID; ID values must be unique (e.g. authorID and artistID can’t be same)

## Keys; the key() function

- Creates an index
- Defined in the stylesheet and not in the DTD/Schema
- Flexible – many keys on one element: one for each attribute.
- Any number of elements can match a given value

## Uses for METS

- From the humble Finding Aid  ... to ...

## METS and Finding Aids

- Beyond the <dao> href pointer
- Useful for managing complex image structure – e.g. multiple scans of multiple pages of letters
- Holistic way to present descriptive metadata along with inline image (all in one package)
- Also useful for presenting technical metadata that EAD does not yet accommodate

## METS Pageturners

- Creates HTML page or frameset with links to resources
- Creates navigable relationships between resources in a METS file
- Creates complex time-based media synchronizationss

## Sfquad.xml redux

- Question: could XSLT mimic java in rendering METS?
- The answer at the time: no
- Dynamic frame reloading a special problem

## N-YHS Edisto Album	

- Album of 77 images from the Civil War period
- Logical structure: album – page - images
- Two to four images per page
- Presented with or without collapsible TOC

## Tokyo Tribunal

- Simple nested structure: jpg page views of Decision taken by the Tokyo Tribunal
- Collapsible TOC to unpack logical structure of various parts

## Afghanistan Digital Library

- 40 books from 1871-1930  (400 eventually)
- Simple structure – no chapters for the most part
- METS Web viewer + PDF / CD version
- Page Images (TIFF at 600 dpi); service files at 98-100 dpi

## CRL Political Web Archive

- Collaboration between Stanford, Cornell, Texas, NYU, IA under aegis of CRL, Mellon
- Sub-Saharan Africa, South East Asia, Latin America, Western Europe
- Testbed: 400 URLs; websites from radical groups, NGOs
- Internet Archive .arc files

## Internet Archive .arc files

- .arc file 100 MB aggregate of harvested files, along with HTTP headers and crawler-generated header for each file
- Fine as a simple SIP, but basically unmanageable as an AIP or DIP
- At present accessed using byte offsets to grab content from aggregate file
- Only searchable by URL (Wayback Machine)

## Can METS save .arc?

- One solution: a METS file for each website contained in .arc
- At collection level, ur-METS file to manage the different versions of website on different dates in different .arcs
- Alternatively, a METS file for each arc, delineating content by byte offset?   Naah.

## It’s the Structure, Silly 

- Ur-METs with <METS:mptr> to versions (cf. serials model)
- Failure of web-archiving access models to date due to indexing at page level only
- Netarkivet.dk – NWA Document format xml document for each page; indexed by FAST
- Results: thousands of hits and no context.