Date:         Mon, 15 Aug 2005 13:16:08 -0400
Reply-To:     Subject Coordinates Discussion List <[log in to unmask]>
Sender:       Subject Coordinates Discussion List <[log in to unmask]>
From:         "Colleen R. Cahill" <[log in to unmask]>
Subject:      Re: Question on form of coordinates (fwd)
Comments: To: [log in to unmask]
Content-Type: TEXT/PLAIN; charset=US-ASCII

Forwarded by Moderator:

As a Geographic Information Systems librarian and graduate of Geomatics, I
am primarily concerned with coordinates which are easily extracted and
mapped.  If one were to create a GIS point or polygon feature class from
MARC records, or use spatial coordinates to search MARC records, the easiest
coordinates to use would be decimal degrees.

However, I am sure you are aware that what you suggest in your message
(N0421510) is not a decimal degree format.  The decimal degree value for the
coordinate you suggest would be 42.252778.
Which is calculated from (15 minutes*60 seconds per minute)+10 seconds = 910
seconds.  910/3600 seconds per degree = 0.252778 + 42 degrees.

In reverse, calculating the minutes and seconds from decimal degrees --
(42.252778 - 42)*3600 seconds per degree = 910.0008 seconds.  910.0008/60
seconds per minute = 15.16668 minutes.  (15.16668 - 15 minutes)*60 seconds =
10.0008 or 10 seconds.  Or similarly 0.252778 sec * 60 min/degree = 15.16668
min.  And (15.16668 - 15 minutes)*60 seconds = 10.0008 or 10 seconds, which
brings us back to 42/15/10.

Instead of using N and E or S and W, the mapping presence is to have any
proposed field use positive values to indicate coordinates in quadrants
north of the Equator and east of Greenwich and negative values for south of
the Equator and west of Greenwich.

The other obstacle to a GIS/MARC interface has been the ability to search
MARC coordinate fields using a patron specified integer coordinate values.
Using a GIS interface it is possible to have patrons select a search area.
It would be wonderful to be able to use the patron's selected coordinates to
search MARC records.  Currently, to the best of my knowledge, coordinate
fields in MARC records are text based which prevent searches for ranges of
integer values.

I look forward to working on this with you and the group.

Thanks
Joe

Joe Aufmuth
GIS coordinator
George A. Smathers Libraries
Government Documents
University of Florida
P.O. Box 117001
Gainesville, Florida 32611-7001
352-273-0367
Fax: 352-392-3357
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-----Original Message-----
From: Subject Coordinates Discussion List [mailto:[log in to unmask]]On
Behalf Of Colleen R. Cahill
Sent: Monday, August 15, 2005 6:56 AM
To: [log in to unmask]
Subject: [SUBCOOR] Question on form of coordinates


As a map cataloger, I primarily deal with coordinates in two forms:
human-readable geographic coodinates (i.e. North 42 degrees, 15 minutes,
10 seconds) and machine-readable decimal degrees (i.e. N0421510). For the
proposed subject coodinates, a machine-readable form of coordinates is
needed and so I always think of decimal coordinates.  This is form a
standard used much?  Are there any other (better or worse) ways used to
present coordinates?

Thank you!
Colleen
 Colleen R. Cahill                   |  [log in to unmask]
 Digital Production Coordinator      |  (202)707-8540
  & Recommending Officer for         |  FAX (202)707-8531
       Science Fiction & Fantasy     |  Library of Congress
These opinions are mine, Mine, Mine! |  Washington, DC 20540-4652