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Date:         Wed, 14 Sep 2005 16:45:22 -0400
Reply-To:     Subject Coordinates Discussion List <[log in to unmask]>
Sender:       Subject Coordinates Discussion List <[log in to unmask]>
From:         Joe Aufmuth <[log in to unmask]>
Subject:      Re: Question on form of coordinates
Comments: To: Subject Coordinates Discussion List <[log in to unmask]>
Content-Type: text/plain; charset="iso-8859-1"

Just a couple of comments, and remember my perspective is as a GIS Librarian educated in Geomatics not library science, but I am learning! I am a glad to see this forum bringing together concerns from a cross section of the information management/systems/science disciplines. I have been involved with GIS consulting for the past 15 years, but only with libraries for the past 5 years. I wish I had been involved with libraries 10 years ago when spatial meta data standards were being developed and proposals were made for their MARC implementation. However as a newly appointed ALA MAGERT CUAC representative I am honored to have this opportunity to represent geospatial interests and work towards solutions on these issues. I am obviously playing catch-up. Is there a mechanism for the spatial data community to provide input to improve the usability of the fields in Proposal No. 94-17, or has that proverbial ship already sailed? Can we re-establish a formal channel/working group to address implementation, or is there an existing group? Perhaps such a representative working group will be the outcome of this discussion list. It would be great if the authority records could become the relational database for the bibliographic records and lead to a GIS interface. Which begs a question about the data formats for coordinate fields in an authority record. Are they alphanumeric or floating point? On authority records for place names: If these have been mentioned in a previous discussion, please excuse any duplication, but I presume we are all aware of the Board of Geographic Names (http://geonames.usgs.gov/bgn.html), the USGS' Geographic Names and Information System (http://geonames.usgs.gov/redirect.html), and the NGA's GEOnet Names Server for foreign names (http://gnswww.nga.mil/geonames/GNS/index.jsp). Besides the current feature names and descriptions which have single Long/Lat coordinates or bounding boxes, USGS also has a list of historic US feature names and coordinates. These would be a great starting point. Or have they already been ingested? One problem we have discussed amongst GIS users in Florida (but have not gone very far with solving), is how to create an authority of existing historic local names for the same "official" GNIS names. As Rebecca points out, we could easily add an alternate name. Realizing of course that over time we may end up with several aliases as well as differing coordinates for the same places. A related topic was brought up at CUAC in May 2005. For historical analysis, there is great interest in preserving as much historic spatial information as possible. If we change the authority record coordinates and the date, how will we preserve historic changes? On 034, 255 fields: Can the data type for these fields be changed from alphanumeric to floating point? I am sure that question will get a good laugh. To work around not being able to use the character based 034 or 255 directly, a colleague and I created a spatially searchable catalog interface using ArcGIS and the GNIS database for Florida. We created a point feature class GIS created from the GNIS coordinate file and populated the database with "hot-linked" purl scripts. A patron could spatially search and then click on the hotlink to run the script and launch a search of our catalog by place name. Additional GIS overlays allowed us to enhance searching using other tabular attributes besides a geographic coordinate reference. This is a very static approach. A more dynamic approach would be to create a searchable GIS database from integer MARC coordinate fields. Or, search the MARC records by a coordinate range and then use the MBR or single coordinate pairs from MARC to create a map/"area of interest". Lastly, to address Rebecca's comment: "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." I am not sure when the format length was adjusted, but I am sure that at the time the change was made I was not in a position in my library career to provide feedback. I also am not sure how or if feedback was solicited from the spatial data experts outside the libraries. When the length was changed, was the data type also changed from alphanumeric to floating point or integer? As evidenced by the leading "+" and "0" used for longitudinal coordinates, my guess is that the field is still alphanumeric. As you know, a leading "+" and "0" are not used with real integer values and a "-" sign could indicate a valid real integer value. So yes, in order to be able to search for a integer value based upon a user specified range (MBR) you would first have to generate a report of MARC's alphanumeric coordinate strings and then strip out the leading "+" and "0" (or parse out the actual values) before "dumping" the coordinates into software to do a mathematical search, or create a GIS database. I suppose you could also write a program to read the alphanumeric string, strip out the leading "+" and "0" and pass the string as a floating point variable for comparison against the user's specified search range. As you also know, the "+" sign is implied with positive values and the "0" is just a hold-over from the DDD/MM/SS format. Both are not really needed. Additionally, a decimal degree value allows a single search statement, where as ddmmss requires additional comparisons of dd, mm, and ss against the user's specified range. Of course you could also write a program interface to convert the string ddmmss to integer decimal degrees and then perform the search. Hope these comments are of interest and assistance. 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 mapper@uflib.ufl.edu <mailto:mapper@uflib.ufl.edu> [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: Friday, September 09, 2005 10:30 AM To: [log in to unmask] Subject: Re: [SUBCOOR] Question on form of coordinates 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 > > (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 > > (http://portal.opengeospatial.org/files/?artifact_id=1094, > > 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 > > > > -- Archie Warnock [log in to unmask] > > -- A/WWW Enterprises www.awcubed.com > > -- As a matter of fact, I _do_ speak for my employer. > > >


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