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Date:         Fri, 9 Sep 2005 10:29:45 -0400
Reply-To:     Subject Coordinates Discussion List <[log in to unmask]>
Sender:       Subject Coordinates Discussion List <[log in to unmask]>
From:         "Rebecca S. Guenther" <[log in to unmask]>
Subject:      Re: Question on form of coordinates
Comments: To: [log in to unmask]
In-Reply-To:  <[log in to unmask]>
Content-Type: TEXT/PLAIN; charset=US-ASCII

I've been following some of the discussion on this list but have been slow to respond. I'm not sure that I understand all the needs of the geospatial community, but do have some thoughts on some of the discussion. Thus far most of this discussion has been about adding coordinates to bibliographic records to be used for more effective searching of places. I think it would be more effective to add the coordinates to authority records instead (or at least as an alternative). The reason is that an authority record is intended to include metadata about the particular entity. So for a person, one could expect an authority record to tell you about that person, like where he/she is employed, when the person was born and died, alternate names. Likewise for a place that authority record could give information about where it is located-- it would be appropriate to include a field to contain coordinates. If over time those coordinates changed because the jurisdiction it covers has changed they could be qualified by date. That way there would be one authoritative source to look for this information. Of course up until now we haven't done that with geographic headings, but I would favor developing a proposal to add the information needed. I would also favor adapting one of the existing fields (034 or 255) rather than defining yet a new field to do what is needed-- and add them to the authority format. Of course for this approach to be effective it would require that systems be able to use it-- a closer interaction between authority and bibliographic records. And the lack of that is the reason why there is this desire to add everything to the bibliographic record. But it does require analyzing where the information rightfully belongs, perhaps in terms of a entity model like FRBR, where there is a distinction between entities and where to record such information. Then the goal would be to get the vendors to implement an effective means of using the data. I think this list is a good vehicle to discuss some of these issues. It would be nice if we could present a discussion paper at the Midwinter MARBI meetings to start getting them out on the table so that any necessary proposals for changes can be considered maybe at the annual meeting. See also below some specific comments on an earlier message. On Tue, 16 Aug 2005, Joe Aufmuth wrote: > The Alexandria project is a prime example of an integer field which will > allow a variable range search. Where as a leading "+" sign and 0 place > holder in MARC limits the records to character based searches. Therefore > additional programming would be required for any MARC catalog interface to > extract the integer values from the character set and then compare them > against a patron's request. It's not the most efficient method. I presume > at the time the change was made to accept some format of decimal degree > coordinates, a visual spatial catalog search engine was not envisioned. A change was made to the format not long ago to make the data variable length, because it seemed too limiting to use a fixed length number of characters in a format that was not widely used (the format that Colleen asked about, e.g. N0421510). So I assume from what you're saying that the "+" and "-" need to be extracted to use the data? I would say that when the change was made noone brought up this point-- we just didn't get enough feedback from experts on geospatial data. > While mapping international dateline spatial data is tricky, treating them > as a series of points is not a problem. If the bounding box column names > are well defined only 2 coordinate pairs are needed, I.E. Upper Left X, > Upper left Y , Lower Right X and Lower Right Y. By definition of a box any > system could read the UL and LR coordinates and calculate the remaining 2 > corners. Or, the additional X,Y coordinates for LL and LR columns could be > included and calculated by a cataloging macro. If the points are treated as > a set of coordinates in a single field additional programming also would be > required to extract the integer values from the set. > > Has anyone seen the Geographic Code Indexing thread on the Maps-L listserv. > Perhaps we can tie in those discussions with ours? I am not a cataloger and > have a very basic question: what does the 052 field offer in terms of format > (integer vs. character), indexing, searching, and reporting? > > And one last larger question. What will come of our discussions? Where is > MARC headed in terms of compatibility with FGDC or other spatial metadata > standards? -- sorry if this is off the thread's topic, but it is another > major issue facing GIS Librarians and digital spatial data related to MARC > records. Will additional MARC fields for digital spatial metadata, be > created? Will existing field formats be changed from character based to > integer based to enhance searching? What is the long term vision for MARC > and spatial metadata? My focus is rather biased towards digital spatial > data indexes and metadata search engines for our patrons. When the Content Standard for Geospatial Metadata was first approved (I think it was 1994), a large proposal went to MARBI to add all elements contained in it so that MARC could carry such data (Proposal No. 94-17). I recall that someone commented that they never saw MARBI approve so many fields at once. We have had very little feedback on the use of any of those changes that were made. Without input from the geospatial community we can't improve the format for its use. Certainly there is a broad recognition that geospatial data is important in the present information environment and we want to accommodate it in MARC as well as possible. So some focused discussion on specific problems and solutions would be welcome. Rebecca ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^ 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] ^^ ^^ ^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Sorry to ramble on > > 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 > [log in to unmask] <mailto:[log in to unmask]> > > > > > > > > > > > > > -----Original Message----- > From: Subject Coordinates Discussion List [mailto:[log in to unmask]]On > Behalf Of Rebecca S. Guenther > Sent: Tuesday, August 16, 2005 10:06 AM > To: [log in to unmask] > Subject: Re: [SUBCOOR] Question on form of coordinates > > > 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 > decimal point. > > Rebecca > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > ^^ 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 > > (, the FGDC > > Content Standard for Digital Geospatial Metadata (CSDGM - > >, various OGC documents > > (, > >, 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 > > > > -- Archie Warnock [log in to unmask] > > -- A/WWW Enterprises > > -- As a matter of fact, I _do_ speak for my employer. > > >

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