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Subject: Re: MAPS-L: Contours and isolines
Date: Mon, 03 Oct 2005
From: David J. Bertuca <[log in to unmask]>
To: Maps, Air Photo & Geospatial Systems Forum <[log in to unmask]>

Hello Harry, Gwen, and fellow mappers,

Your descriptions of the uses of contours, etc. are proper for describing
their uses on maps, however, when cataloging a map, there are fewer
parameters and the description of contours is limited in scope to describe
physical elevations only on maps. LC's Map Cataloging Manual and other
cataloging instructions (i.e., AACR2) are mainly concerned with description
of the physical relief.

The other uses of "contours" and other terms can be taken care of using
note fields. This also has the advantage that you can use terms that can be
searched, and that can better describe the map's features.

This is a really quick answer, but it should help for cataloging purposes.
This also describes Nancy K's comments on relief that is other than for
elevation.

David Bertuca

--On Friday, September 30, 2005 2:20 PM -0500 "Angie Cope, AGSL"
<[log in to unmask]> wrote:

> ================================================
> MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L ** MAPS-L
> ================================================
>
> Subject: Contours and isolines
> Date: Fri, 30 Sep 2005
> From: Harry O. Davis <[log in to unmask]>
> To: [log in to unmask]
>
>
> I concur in the concern presented by Nancy Kandoian and the remarks
> offered
> by Russell Guy concerning relief.
>
> To limit one's conceptualization and use of the term "contour" to only
> surface expressions of elevation above sea level is at odds with what is
> found on some maps.  Although it might be argued that one should use only
> "isoline" (or a cognate term such as "isopleth" or "isopach") and not
> "contour" when identifying a sub-sea or subsurface situation, the reality
> is that "contours" (with contour intervals) appear on many geologic and
> geophysical maps, either as elevation or depth measurements and also as
> expressions of other parameters (such as gravity intensity).
> Additionally,
> an argument can be made that isolines showing depth (inverse relief) are
> negative contours, or, more correctly, contours with a negative value
> relative to sea level.
>
> To complicate matters further, note that the term "bathymetric contour" is
> employed in the USGS 1:100,000-scale topographic-bathymetric series.   And
> people do speak of the "relief of the ocean floor."
>
> Then there is the need to distinguish between absolute relief (altitude)
> and relative relief.
>
> Looking at our collection here I find maps whose titles speak of "bedrock
> surface," "contoured base [of a formation]", "structure on top of ...,"
> "depth to bedrock," "subsurface contour map," etc., all using contours
> with
> contour intervals.  Then there are other maps (such as those showing
> thickness of glacial drift) that employ isopachs or other isolines.
>
> The responses to Gwen's question still leave me uncertain as to when a
> cataloger should code relief and when not to.  And if there are contours
> or
> other isolines present on the map depicting other than surface
> (topographic) relief, what is the appropriate coding?
>
> Thanks for any additional insight into all this.
>
> Harry Davis
>
>
>
>
>
> Harry O. Davis
> Map Librarian
> Morris Library / MS 6632
> 605 Agriculture Drive
> Southern Illinois University
> Carbondale, Illinois 62901
>
> Phone:  618-453-2372 or 618-453-2705  <> FAX:  618-453-2704
> Internet: [log in to unmask]
>
>



David J. Bertuca
[log in to unmask]


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