Our ref: 32695
29 JUL 1997
Robert A Baron has suggested that we should send details of our date
tool for publication on Museum-L. Here is a brief description from
our brochure on COLLECTION:
DATE TOOL
Dates occur extensively in museum records and frequently have ranges
uncertainties, imprecisions and ambiguities. COLLECTION has an
extremely powerful and flexible date handling facility.
A parameter switch defines the style of date used at the site
(European, US, etc) which determines how dates are interpreted for
input validation and output display.
A date can be input with varying degrees of precision and in a variety
of formats. Dates can be entered as a single date or as range. AD
dates are assumed unless BC is specified, and AD is only displayed
where AD is specified. The current year and century can be omitted on
input of precise dates.
Qualifiers such as Early, Mid, Late, Pre, Post and Circa, and their
synonyms may be used and uncertainty can be indicated by adding a '?'
to a date, by placing the date in parentheses eg (1898), [5th Century
BC], or by the use of keywords such as Indeterminate or Unknown.
Seasons can be specified in conjunction with a year eg Spring 1971.
Format Input Examples
day month year 1 Jan 1890, 1 Feb 95, 12/2
month & year January 1890
year 1666, 5 AD, BC 1200
decade 1920s, 80s AD
century 19th Cent BC, 1600s, 17 century
millennium 5,000 YA, 250,000 BP
imprecise Late 12th Century, Circa 1870s, Post 600 AD, Mid 1920s
range Jan 1890-12 Feb 1897, 5BC - 5AD, 1860s-1911, 1887-9, 1967-76
Dates input are tightly validated in accordance with rules and their
parameters. The date is then stored in an internal compressed format,
and is displayed in a consistent interpreted style (e.g. 1600s is
entered but is displayed as 17th Century).
Notes can be input with any date by enclosing these in curly brackets,
e.g. `Circa 1600 {based upon radio-carbon dating analysis}'.
A date field may have an associated Period field which may be used
instead of, or in conjunction with a date entry. Thus an object can be
ascribed to the Victorian period (1837 to 1901), as well as, or
instead of, being specifically dated. If only the period is used then
it is date indexed using the period dates.
The system calculates earliest and latest dates for each entry. taking
account of qualifiers such as Early, Mid and Late, which compress the
range, and Circa, Pre and Post, which extend it e.g. Circa a year date
is +/- five years, Circa a decade date is +/- one decade, the Late
part of a century is the last third. The earliest and latest dates
calculated by the system may be overridden by user input.
Dates are explosively indexed according to rules defined in parameters
for each date field. Thus a date such as 4th July 1990 would be
indexed and retrievable as; 4 July 1990, 4 July, July 1990, 1990,
1990's and 20th Century.
Date qualifiers like Early, Mid, Late, Circa, Pre and Post, adjust the
indexing. For example, if Circa a decade was specified as being +/-
one decade, then Circa 1890s would be indexed and retrievable as
1880s, 1890s, 1900s, 19th Century, and 20th Century.
Retrieving records using the date indexes is easy and fast. The date
or range you want to retrieve on is entered in the same way as a date
entry (e.g. Late 16th Century, Circa 1940, May 1950 - 12 Sep 1951).
The user does not need to concern themselves with the format which was
used on entry when making a retrieval. For example, a search for 1960s
objects would find not only items catalogued as 1960s but also any
date which could fall in the 1960s e.g. 1959-1961, Circa 1959, 12 Jan
1967, Post 1955.
We would welcome any comments or suggestions on this most challenging
aspect of museum software.
Matthew Crozier
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Vernon Systems Ltd. Vernon Systems COLLECTION
P.O. Box 6909 -- the world's most admired
Auckland, New Zealand collections management system.
Ph: +(649) 302-3147 +-----------------------------------------------
Fax: +(649) 302-3150
Email: [log in to unmask] 100033,673 (CompuServe)
WWW: http://ourworld.compuserve.com/homepages/vsl
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