=======================================================================

MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L

 =======================================================================

Date: Fri, 8 Apr 2005
From: "Barry, John W. [C]" <[log in to unmask]>
Subject: RE: MAPS-L: RE: Records to Pieces Ratio

Jenny,
At NGA (United States National Geospatial-Intelligence Agency), we
catalog every sheet with one (or more, see below)bibliographic record in
our Voyager system.  Each sheet in a series has its own bib record, and
if the sheet has insets, each inset gets cataloged as well, in a
"bound-with" relationship with its parent.  Foreign/native products are
handled the same way.  As we have multiple holdings locations, each
location can have a various number of copies.  We have found that an
estimation of the bib to sheet ratio depends on a variety of things:

    * Are there insets?  Hydrographic sheets commonly have at least 1-4
      insets.  Topographic sometimes have only 1.
    * How many locations hold this item?
    * Is it NGA or non-NGA (native product)?
    * How many copies are retained at each location for the item type?


We find that it is impossible to set an average ratio over the entire
collection, since native Topo lithos may be 1:1 (one copy held at one
location) while Hydro DNCL's can be 1:10, and NGA series sheets can be
1:20 (they are held all over the place).  We are trying to get to a
state of 1:1 by digitizing our collection and retaining only one
archival copy, but we are years from achieving that.

So, as for your question:
Is there any kind of ratio that can be expected for the number of
bibliographic records to the number of pieces in a "typical," fully
cataloged map collection?
I would have to say "No", since the ratio depends on many factors which
may be atypical or unique to your own collection, your own method of
"full" cataloging, and your own retention policy.

v/r,
John W Barry [C]
National Geospatial-Intelligence Agency (NGA)
Software Engineer
EDC / e-Library Team
Bethesda, MD
(T) 301-227-2103 (F) 301-227-5059

"To understand your enemy, you must walk a mile
in his shoes.  Then, if he is still your enemy, you are
a mile away and he has no shoes."





    -----Original Message-----
    From: Angie Cope, American Geographical Society Library UWM
    [mailto:[log in to unmask]]
    Sent: Friday, April 08, 2005 1:13 PM
    To: [log in to unmask]
    Subject: MAPS-L: RE: Records to Pieces Ratio

 =======================================================================

MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L

 =======================================================================

Date: Fri, 8 Apr 2005
From: Paige Andrew <[log in to unmask]>
Subject: Records to Pieces Ratio

    Jenny,

    As you know, I've been working in two major map collections over
    nearly 20 years, so I do have a "feel" in regards to your question,
    assuming that both large map collections (Univ. of Georgia and Penn
    State) are "typical" in scope and content. Please don't hold me to
    these numbers as being anything near accurate and/or scientific, but
    I think its about a 3 to 1 ratio of individual sheets/pieces to
    bibliographic records.

    I'm interested in seeing other comments towards your question too.

    Paige

    p.s. Looking forward to seeing you in DC in May!

    At 11:15 AM 4/8/2005, you wrote:

>     ========================================================================
>
>     MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L
>
>     ========================================================================
>
>     Date: Fri, 8 Apr 2005
>     From: Jenny Marie Johnson <[log in to unmask]>
>     Subject: Records to Pieces Ratio
>
>     Hi.
>
>     This probably is one of those questions that can't be answered --
>     although for some reason I vaguely remember reading or hearing a
>     discussion about it.
>
>     Is there any kind of ratio that can be expected for the number of
>     bibliographic records to the number of pieces in a "typical," fully
>     cataloged map collection?  Is there any way of saying "Since we have
>     x,000 pieces we can expect to find y,000 map records in the online
>     catalog?"
>
>     I'm not expecting there to be a truly scientific ratio!  Commonsense,
>     wisdom from the ages, or folklore/urban myth -- all ideas will be
>     helpful!
>
>     Thanks!
>
>     Jenny Marie Johnson
>     Map and Geography Librarian and
>     Assoc. Professor of Library Administration
>
>     University of Illinois at Urbana-Champaign


--