---------- Forwarded message ----------
Date: Tue, 7 Aug 2001 14:58:20 -0400 (EDT)
From: Ken Grabach <[log in to unmask]>
To: [log in to unmask]
Subject: remote-sensing subject question

Last week I posed the question concerning the difference between the term
'remote-sensing image' and the term 'remote-sensing map' as they should be
applied as format subdivisions to geographic subject headings, that is,
delimiter v subfield of field 651 headings or of field 650 headings with
delimiter z subfields.

I received two replies, and I would like to summarize them, as I found
them useful.  I presume others will, as well.

I asked this question in the first place because I have found the
application of these headings to be confusing.  Or, if I understand their
meaning, those applying them have betrayed their own confusion.  I had
been finding a number of maps that employ satellite imagery as the base
for the published map.  In these instances finished product appears to me
to be a map based on satellite imagery, not a satellite image, per se.

Yet, in many cases, the sole term that was applied in the subject heading
has been  'v satellite-images.'  The Armenia sets did, indeed, get
satellite map as at least one sub-heading, but other maps that are
similar in format have not.  Thus I posed the question.

Dan Seldin at Indiana University refers to discussioned at a breakout
session at the WAML meeting at LC several years ago, where the
distinctions in the headings was raised.

'Remote-sensing images--As it says in the 360 field of the authority
record, "for images of those places obtained through remote-sensing
processes."  Remote-sensing maps--As it says in the 260 field of the
authority record, "for remote-sensing images upon which grids and other
mapping data elements have been added."'

He also mentions a 670 in this latter record, which refers to a
conversation with Mary Larsgaard who said that 'remote sensing maps' is a
term used by map librarians that is not found in printed sources.

Barbara Storey, Cataloging Team Leader with Geography and Maps Division of
the Library of Congress, also replied.  She said the interpretation I had
assumed, and given in my query, was correct.  That is, that they use
Remote-sensing maps when the satellite image has been enhanced in the
published item.

I raised the question of how the term Orthophotomaps is applied, and how
it is distinguished in cataloging practice from the others.  Dan Seldin
provided some excellent definitions.  He quotes two definitions from
"Maps for America": 'an orthophotograph is a "photograph having the
properties of an orthographic projection.  It is derived from a
conventional perspective photography by simple or differential
rectification so that image displacements caused by camera tilt and
terrain relief are removed."  In other words, images on an orthophotograph
are positionally accurate.  An orthophotographic map, is a "Map produced
by assembling orthophotographs at a specified uniform scale in a map
format.  An orthophotomap is an "Orthophotographic map with contours and
cartographic treatment, presented in a standard format, and related to
standard reference systems."'

Barbara Storey comments that her team regard orthophotomaps as a type of
remote-sensing map.  It appears, from a search of the database that the
heading "Orthophotomaps" has only been used twice, both for books
published in the 1970s.  I presume, from this, that Orthophotomaps would
most properly not be used as a format subdivision, but is instead a direct
subject heading, applied to materials about orthophotocartography, if that
poly-syllabic jumble can be considered a word.  On the other hand, an
example of such would be treated with the subdivision Remote-sensing maps.

My thanks to Dan and Barbara.  Both confirmed my understanding, and helped
clarify their usage.  Barbara in particular helped to alleviate my concern
over the possible redundance between Orthophoto... and Remote-sensing
maps.

I hope this might help some others of you as it has me.

With best regards,

___________________________
Ken Grabach                           <[log in to unmask]>
Maps Librarian                         Phone: 513-529-1726
Miami University Libraries
Oxford, Ohio  45056  USA