8 August 2001


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Approved-By: Johnnie Sutherland
Date: Tue, 7 Aug 2001 16:30:21 -0400
Reply-To: Maps and Air Photo Systems Forum
Sender: Maps and Air Photo Systems Forum
From: Johnnie Sutherland
Subject: remote-sensing subject question (fwd)


---------- Forwarded message ----------

Date: Tue, 7 Aug 2001 14:58:20 -0400 (EDT)
From: Ken Grabach

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 <>
Maps Librarian Phone: 513-529-1726
Miami University Libraries
Oxford, Ohio 45056 USA