-------- Original Message --------
Subject:        Re: MAPS-L: cataloging question: bathymetric formlines?
Date:   Tue, 27 Dec 2005 14:50:49 -0500
From:   [log in to unmask]
To:     Maps, Air Photo & Geospatial Systems Forum <[log in to unmask]>



hi all;

If the isolines depict actual depth "contours" or approximate depth
areas, then they can be called isolines. in the 19th century they did
quite a bit of depth data gathering (oddly enough, some of our more
current charts still refer to this data in many locations).

If the lines are unrelated to depth, but instead show "good fishing
banks" without reference to some sort of depth data, then you might have
a different situation.

not seeing the map/chart in question, but from your description, I would
think that they charted approx. regions and that the isolines do indeed
show general depth information.

On some early (and later as well) maps and charts, depth is represented
with general layers using tinted shades of blue. these are called
hypsometric tints, or "depth tints" and denote general "contours" of the
sea floor. They are usually still based on data of some sort though.

isolines usually (but not always) show a depth somewhere along the line.
exceptions might be a chart that states in the legend that only certain
depths are shown with isolines (e.g., "isolines show 5 fathom depth").
this is used mostly to show atolls, reefs, or sandbars, etc. and is
helpful for general navigation only.

See if any of this comes close to matching your item. If not, please
provide more info on the map/chart.

David Bertuca, Map Librarian
University at Buffalo

Quoting Angie Cope <[log in to unmask]>:

> -------- Original Message --------
> Subject:        cataloging question: bathymetric formlines?
> Date:   Fri, 23 Dec 2005
> From:   Christopher Winters <[log in to unmask]>
> To:     Maps, Air Photo & Geospatial Systems Forum
> <[log in to unmask]>
>
>
>
>
> We have a group of 19th-century maps by Felix Ansart that use what
> appear to be bathymetric isolines in a, well, rather impressionistic
> way to show fishing banks, approximate continental shelf boundaries,
> etc.
>
> In map-cataloging English, are these bathymetric form lines (that
> would be noted in the 008 relf field by f), or, in light of the
> limited knowledge of ocean depths at the time, should we charitably
> call them bathymetric isolines--or perhaps forget we noticed them
> at all?
>
> Advice would be greatly appreciated!
>
> Chris Winters
> University of Chicago Library
>
>
>



David J. Bertuca
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