Site Content

The Digital Bridges Web site consists of a collection thirty representative 19th century American bridge engineering monographs, manuals, and documents from the Lehigh University Libraries' Special Collections. Many of these items are relatively rare an in some cases quite fragile.

With the growing interest in material culture, technology studies, the history of engineering practices, and the renovation and restoration of historical structures, this site is designed to provide a rich, interactive research tool for students, historians, and engineering professionals.

The source documents have been scanned, converted to text, and partially-corrected to make all significant terms, personal, and proper names retrievable through the site search engine. In addition, all items in the collection have been structured for browsing in the manner of a book, with organization units such as chapters and subchapters randomly viewable, and with page-to-page forward and back links.

Project Background

Underwritten in part by Library Services & Technology Act (LSTA) funds administered through the Pennsylvania Commonwealth Library's NETShare program, the Digital Bridges Web site was developed by a team of librarians and technical staff within Lehigh University's Library and Technology Services organization, with significant contributions by several independent professionals with whom Lehigh University contracted for specific services.

Major development and production activities for the site occurred from May 2001 through March 2002, but a number of key site enhancements are still in process as of this writing (April, 2002). Members of the Digital Bridges project team include (individuals are affiliated with Lehigh University unless otherwise noted):

Marie Boltz, Library Assistant
Metadata Input

Ilhan Citak, Special Collections Assistant
Scanning & Production Management, Editorial Oversight

Jennifer Hanf and Andre Szejko of Hanf Design, Inc., Kutztown, Pennsylvania
Site Graphics and Interface Design

Joe Lucia, Director for Library Systems & Access
Project Planning & Administration, Technical Consulting

Tim McGeary, Library Systems Specialist
Server Adminsitration & Support, Ongoing Site Development

Judy McNally, Senior Cataloging Librarian
Metadata Development & Production, Site Quality Control

John McPherson, New Zealand Digital Library Project, University of Waikato
Greenstone Software Modification and Development

Philip Metzger, Curator of Special Collections
Project Planning, Materials Selection, Metadata Development, Documentation

John Misinco, Student Assistant
Document Scanning & Editing

George Motter, Senior Systems Specialist
System Administration, Programming, Technical Problem Solving

Svetlana Oshkai, Graduate Student Assistant
Production Process Development, Document Scanning & Editing

Christine Roysdon, Director for Collection Management
Project, Planning, Metadata Development & Production, Site Quality Control

Site Design & Development

Graphical and interface design for the site was provided by Hanf Design of Kutztown, Pennsylvania. Ornaments and illustrations on the site main page were drawn from volumes included in the online collection. The title pages from each volume in the collection include a representative illustration or "signature" design element from the printed book. Navigational graphics and menus were also developed to reflect the historical character of the collection. At the level of individual book and page views, the design goal was to preserve in the online form of each document as much as possible of the look and feel of the physical volumes themselves.

Production scanning of volumes for the site was completed using a Minolta PS 7000 overhead scanner. Archival scans of all items were made at 600 DPI and stored in TIFF format. From these sources files, 150 DPI (full page view) and 50 DPI (thumbnail) JPEG files were generated, along with PDF versions of these image files for facilitating print output by end-users. Much of the file conversion work was automated through use of a series of macro utilities. Optical character recognition (OCR) software was used to generate searchable text from the page scans. To facilitate text retrieval, rough edits (working from printed source documents) of the converted text were completed to make certain that all important words (personal names, bridge names, locations names, key engineering terms, etc.) were correct.

A series of Unix and Perl scripts were developed to "wrap" the raw page files in HTML. The Metabrowser software was used to apply descriptive and structural metadata to these HTML documents. Creating structural metadata to bring together internal organizational units from the printed volumes (chapters, subchapters, sections, pages, etc.) and render these usable by the site database engine proved to be an enormously complicated challenge. The converted text data from each scanned page was loaded into a metadata field in the source HTML to render it indexable by the site search engine.

Server Technical Information

The Digital Bridges site runs on a Dell Pentium III server class machine with 512MB of RAM and 30GB of redundant disk. The server operates under RedHat Linux version 7.2 and utilizes the Apache Web software for page service and the Greenstone Digital Library software for organization, indexing, retrieval, and dynamic page creation for materials in the online collection. Extensive local Perl and Unix shell scripts support generation of site pages within Greenstone. Information of the Greenstone software, and open source solution for digital library applications developed in New Zealand, can be found at http://www.greenstone.org/english/home.html

Ongoing Work

As of this writing, the site glossaries and the site list of illustrations are still under development. The organization and display of search results within the retrieval is also undergoing refinement.

Page information last updated: April 29, 2002 by J.Lucia