INDEXING TECHNIQUES
The process of constructing document
surrogates or document representations is
called as Subject Indexing.
Indexing has to specify exactly the content
of documents. This needs a language by
which the contents could be described
precisely (i.e. Indexing Language).
Indexing includes :
a) Conceptual Analysis, and
b) Representation (of the Contents)
Types of Indexing Techniques :
There are broadly two types of Indexing
Techniques or Indexing Methods. They are :
a) Pre-Coordinate Indexing, and
b) Post-Coordinate Indexing.
Pre-Coordinate Indexing Systems : A Compound
or composite subject is analyzed into its
constituent concepts according to a plan and
these constituent concepts are then represented
by symbols (when using a Classification Scheme)
or Words of the Indexing Language in use. The
next step is to synthesize or combine the
components in order, according to the rules of
the language (i.e. coordination of concepts).
• That is the Coordination of concepts contained in
a documents is done in-anticipation of readers
approach.
• In Pre-coordinate Indexing systems, the Subject
Heading consists of two or many index terms and
these terms are arranged in a pre-determined
order using its own syntax or the citation order.
• The Characteristics of Indexing language are
the syntax, the method of rotation or cycling of
components, the significant word order, use of
relationship symbols, system of references, etc.
• The examples are : Chain Indexing, PRECIS,etc.
Post-Coordinate Indexing Systems:
A compound or composite subject is analyzed into
its constituent components, but they will be kept
separately uncoordinated by the indexer.
• Coordination of concepts is done at the time
of search by the user.
• These indexing systems could bypass /
overcome the most difficult question of deciding
on an order of significance (which eventually
controls the approaches that could be provided
by a pre-coordinate Indexing system).
• E.g. Uniterm Indexing; Zatocoding system;
Optical coincidence methods(Peek-a-Boosystem)