For the record, I thought I would mention that a few years ago we made
some changes to the MARC field that contains the structured form of
coordinates, field 034 (MARC also has a field for the human readable form,
field 255). Field 034 has separate data elements (subfields) for
westernmost, easternmost, northernmost and southernmost coordinates. We
changed it to allow for variable length values and to use either the form
Colleen asked about (e.g. N0421510) or decimal degree format (e.g.
+079.533265, etc.). At the time we made this change, we were told that
there was not a need to specify the format used, since the format is
easily recognized by the number of characters and the placement of the
^^ Rebecca S. Guenther ^^
^^ Senior Networking and Standards Specialist ^^
^^ Network Development and MARC Standards Office ^^
^^ 1st and Independence Ave. SE ^^
^^ Library of Congress ^^
^^ Washington, DC 20540-4402 ^^
^^ (202) 707-5092 (voice) (202) 707-0115 (FAX) ^^
^^ [log in to unmask] ^^
On Mon, 15 Aug 2005, Archie Warnock wrote:
> Colleen R. Cahill wrote:
> > 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?
> Thanks for getting this started, Colleen.
> Decimal degress are, I think, to be preferred in almost all cases
> although there are certainly occasional needs for alternative coordinate
> reference systems. Decimal degrees are trivial for machines to parse,
> they sort sensibly and are even relatively easy for humans to read.
> Metadata standards, eg, the Z39.50 GEO Profile
> (http://www.blueangeltech.com/standards/GeoProfile/geo22.htm), the FGDC
> Content Standard for Digital Geospatial Metadata (CSDGM -
> http://www.fgdc.gov/metadata/csdgm/), various OGC documents
> https://portal.opengeospatial.org/files/?artifact_id=6716), to the
> extent that they address spatial coordinates at all, require the use of
> decimal degrees.
> A bigger issue with geographic coordinates, it seems to me, is ensuring
> that the coordinates are treated together, not as individual bounding
> coordinates. That is, a bounding rectangle needs to be considered as a
> _set_ of 4 coordinates and handled together, rather than as 4
> independent points. Otherwise, footprints that cross the International
> Date Line become much harder to handle.
> -- Archie Warnock [log in to unmask]
> -- A/WWW Enterprises www.awcubed.com
> -- As a matter of fact, I _do_ speak for my employer.