1. THESAURUS CONSTRUCTION: GROUND WATER
Madely du Preez

2. Controlled vocabularies
Two indexing languages:
Natural language
Controlled vocabularies
Examples of controlled vocabularies:
Thesauri
Ontologies
Taxonomies
folksonomies

3. Definitions INS3707 Study guide definition:
A thesaurus is a systematic, organised aid which can assist indexers and users of IOAR systems to identify relationships and preferences between terms in order to index and retrieve documents
National Information Standards Definition:
A thesaurus, for the purpose of this standard, is a controlled vocabulary of terms in natural language that are designed for post coordination. The need to control the formation and use of terms stems mainly from two basic features of natural language, namely synonyms (different terms representing the same concept) and polysemes or homographs (terms with the same spelling representing different concepts).

4. Characteristics Alphabetically and hierarchically structured
Indicate variety of indexing terms
Includes references to preferred terms
Indicates relationships among terms

5. Hierarchical relationships
Broader to narrower terms
BT Transport
NT Road transport
Air transport
Shipping
Narrower terms can also be broader terms:
BT Road transport
NT Buses
Motor cars
Trucks

6. Equal relationships and scope notes
E.g. buses, motor cars, trucks
Includes scope notes:
“A Scope Note is a brief statement of the intended usage of a Descriptor. It may be used to clarify an ambiguous term or to restrict the usage of a term. Special indexing notes are often included.” (Eric Thesaurus Fact File)

7. Types of Thesauri
General or multidisciplinary thesauri, e.g. Eric and ISAP thesauri
Thesauri describing specialised collections can be multidisciplinary: art collections
Thesauri for specialised collections: INIS for Nuclear energy information

8. Purpose of thesauri in information retrieval
Used to describe contents of a document
Information retrieval systems:
Identify terms relevant to an information need
Narrow information searches
Ensures the retrieval of information in an IRS
Promote a general idea of a subject field
A semantic map of the interrelationships between terms
Provide definitions for terms

9. Indexing terms INDEXING TERM Preferred terms Non-preferred terms
(used for)
Non-preferred terms
(use)

10. Typical thesaurus entry
INDEXING TERM SN (scope note) UF (used for) BT (Broader term) NT (Narrower term) RT (Related term)

11. EXAMPLE
BREAD SN A staple food made from flour or meal mixed with other dry and liquid ingredients, usually combined with a leavening agent, and kneaded, shaped into loaves, and baked. BT Staple food RT Rice NT Ingredients Rye bread whole-wheat bread

12. Typical thesaurus entry (2)
The nature of the indexing term determines the relationship
Not every indexing term has a relationship with other terms – they are orphan terms
Synonyms: choose one and indicate preference as follows:
INDEXING TERM
U (Use)
Example:
Leavening agent
U YEAST

13. Indexing terms Scope notes
Use scope notes to
Indicate a series of subjects to be covered
To give instructions to indexers
To explain terms which have the same spelling but different meanings (homonyms)
Not all indexing terms require scope notes

14. Equivalent relationships between indexing terms
leavening agent
U YEAST
YEAST
UF leavening agent
RECIPROCAL ENTRY

15. Hierarchical relationships between indexing terms
STAPLE FOOD
NT Bread
BREAD
BT Staple food
RECIPROCAL ENTRY

16. Relationships between indexing terms
Nonhierarchical / equivalent relationships
BREAD
RT Rice
RICE
RT Bread
Reciprocal entry

17. My Thesaurus
BREAD
BT Staple food
RT Rice
FLOUR
BT Ingredients
RT Yeast
INGREDIENTS
NT Flour
Yeast
Leavening agent
U YEAST
RECIPES RICE BT Staple food RT Bread STAPLE FOOD NT Bread Rice YEAST UF Leavening agent BT Ingredients RT Flour

18. Guidelines for formulating thesaurus entries
Nouns and noun phrases
Distance learning
Use adjectives as indexing terms in exceptional cases
Miniature sizes ; portable devices
Avoid adverbs and verbs
Book evaluation not evaluation of books
Singular vs plural form
Nouns for tangible objects that can be counted – plural: dogs, cats
Non countable nouns – singular: sugar
Spelling
Colour vs color
Punctuation
Letters (alphabet) / Letters (correspondence)
Multicultural societies not multi-cultural societies
Abbreviations
SADEC / Southern African Development Community
Compound terms:
Dried fruit; municipal engineering; corporate bodies

19. ACTIVITY Construct a thesaurus
Age (of water)
Aquifers
Boreholes
Drilling
Geohydrology
Hydrology
Hydrogeology
Ground water
Ground water contamination
Ground water management
Groundwater
Pumping tests
Recharge
Seepage
Springs
Sustainable yield
Unsaturated zones
Water tables
Wells
Yield

20. ANY QUESTIONS?