Document Objects: Their Formats, Storage and Processing

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Document Formats and Their Characteristics
T.B. RajashekarNational Centre for Science
InformationIndian Institute of ScienceBangalore
560 012 (E-Mail raja_at_ncsi.iisc.ernet.in)
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About This Presentation

• Goal To understand different characteristics of
  document formats

• Related reference
• Selecting Electronic Document Formats, by Gary
  Cleveland, IFLA UDT Programme. August 1999.
  www.ifla.org/VI/5/op/udtop11/udtop11.htm

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Why Study E-Documents?

• E-documents are at the core of DLs
• Irrespective of variety of metadata, search and
  browse features supported by a DL, users are
  ultimately interested in gaining access to
  e-documents
• Issues related to their creation, storage and
  retrieval are therefore of key importance

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E-document Formats

• Characteristics of an e-document are determined
  by its format
• These characteristics also determine the
  processes and technologies used for their
  creation, storage, indexing, retrieval, and their
  appropriateness for use in DLs
• Understanding these characteristics is useful in
  assessing the importance of different e-document
  formats

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Characteristics of E-document Formats

• Machine-readability
• Multi-lingual characters
• Layout retention
• Editability
• File size
• Multiple-page
• Structured or non-structured

• Multimedia
• Support for links
• Screen display
• Printing
• Resource overheads
• Degree of usage
• Cost

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Characteristics

• Machine-readability
• Ability to recognize text within a document
• Required for indexing and searching
• Many formats need special processing to identify/
  extract text
• Display of multi-lingual characters
• Ability to display characters of different
  languages

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Characteristics

• Layout retention
• Degree to which a document preserves the look of
  the original document
• Editability
• Does the format allow editing of its content?
  Level of ease/ difficulty
• Multiple-page
• Does the format support inclusion of all pages of
  a document within the same file?

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Characteristics

• File size
• Same document rendered in different formats
  occupies different storage
• Related issues storage space, server speed,
  bandwidth server, user
• Structured, non-structured
• Explicit identification of document elements like
  author, title, chapters, sections, etc.

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Characteristics

• Multimedia
• Does the format support multimedia?
• Does our material require such support?
• Support links
• Linking capability compound documents,
  multimedia
• Screen display
• Is the document to be primarily read online?
  (e.g. website pages)

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Characteristics

• Printing
• How well and how easily the format prints on
  paper
• Resource overhead
• Tools required for creation
• Complexity of preparation
• Skills needed for preparation

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Characteristics

• Degree of usage
• Degree of usage of the format how common is its
  usage
• Cost
• Cost for creation and maintenance s/w, h/w,
  staff, training, available funding

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Common E-document Formats

• Image formats
• TIFF
• GIF
• JPEG
• Basic text formats
• ASCII
• UNICODE
• RTF
• Presentation formats
• Postscript
• PDF

• Structured formats
• HTML
• SGML
• XML
• Audio and video formats
• Audio Wave, Real Audio, MP3
• Video AVI, MPEG

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Image Formats

• Used to display digital images of text pages,
  photographs, illustrations, artwork, and other
  graphical material.
• Digitization digital images of paper
  pages.
• Common image formats in use include TIFF, GIF,
  and JPEG.

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Basic Text Formats

• Simplest form of electronic documents
• Contain only a simple string of characters and
  are devoid of more complex information
  (structure, layout, diagrams, etc.)
• ASCII (8 bit, Latin chars), UNICODE (16 bit,
  65,536 chars all major written languages)
• RTF (Microsofts text format with some formatting
  support)

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Presentation Formats

• Formats that have been developed for on screen
  display or printing.
• Also called as page description formats.
• They are typically static, single file formats
  that do not contain any structure information.
• Common presentation formats Adobe PostScript and
  Adobe PDF.

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Structured Formats

• Formats that support explicit tagging of document
  elements
• Formats under this category
• SGML (Standard Generalized Markup Language)
• XML(Extensible Markup Language)
• HTML

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Table giving detailed comparison of
characteristics of different document formats