At 12:29 AM 7/16/97 -0500, Orycteropus afer <[log in to unmask]> wrote:

>There are a few places in museum automation systems where date type fields
>are appropriate such as in those fields used to automatically record when a
>record was created or updated.   In general, though, date type fields are
>not a good solution for recording the kinds of dates found in museum
>documentation.
>

The best dating algorithm I've ever seen in a museum cataloging/object
management system is that used by Vernon Systems. It has the ability to
understand a wide variety of date notations, even those that are less
numeric and more text, and to process them as fuzzy boundaries of date ranges.

Vernon Systems monitors this list; perhaps someone there would want briefly
to explain what their date facility can do.

One of the more difficult problems to solve in representing dates is the
use of similar date formulas to represent different phenomena.  The most
simple example of this concerns the use of expressions like "circa."  Circa
to one scholar may indicate one degree of probability and to another
scholar an entirely different range; more confusing still, however, is when
"circa" has no arithmetic significance, and just indicates indecision or
proximity to another (unnamed) work.  In addition, "circa," when used to
describe the date of events in one area, may have an entirely different
meaning when used for another culture and/or period.

Calendar translation is always a problem when rendering dates.  Not every
calendar in use can be precisely mapped to the one we use.  Even the
correspondence between Julian and Gregorian calendars presents problems,
since the Gregorian Calendar was not adopted at the same time all over the
Western World.  A date without a calendar is like a dimension without a unit.

A number of local practices used to render dates can also be confusing.
One museum in which I had opportunity to examine records used of A.D. after
a date to indicate that the date was transposed from another calendar,
while the date without A.D. indicated that the date was not translated.

In many instances dates are not facts but opinions, and the record must be
able to indicate the sources of the opinion, be it that of a curator or
that of a scholar from whose work the date has been taken.  Because dates
are often opinions, the representation of a date in a record should not
necessarily supplant a previous date; rather, they should be collected
(with sources) as multiple values in a matrix of date/source data structures.

Aside from the problem of how to render and understand dates, when entered
into a live database, dates (dates of attribution, mostly) cannot be
disconnected from the context in which they were formulated.  In a book,
when a scholar makes an attribution and applies a date, that information is
inexorably tied to the name of the scholar and to the facts associated with
the edition.  In a live database, however, dates presented without
authority are essentially meaningless, or will be as soon as memory of
their origin fades.


===========================
Robert A. Baron
Museum Computer Consultant
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