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DATE: May 27, 2021
NAME: Broadening Scope of Field 034 for Geographic Coordinates in the MARC 21 Bibliographic and Authority Formats
SOURCE: Canadian Committee on Metadata Exchange
SUMMARY: This paper proposes modifications in field 034 (Coded Cartographic Mathematical Data) in the MARC 21 Bibliographic and Authority Formats to allow for the recording of geographic coordinates, when appropriate, for any type of resource
KEYWORDS: Field 034 (BD, AD); Coded Cartographic Mathematical Data (BD, AD); Geographic Positioning (BD, AD); Geographic Coordinates (BD, AD)
05/27/21 – Made available to the MARC community for discussion.
06/28/21 – Results of MARC Advisory Committee discussion: Approved, with the following editorial amendment to the proposed field definition and scope:
"For non-cartographic materials (i.e., images, graphic materials, textual materials,
etc.), geographic coordinates are recorded to represent the position of the
structure, site or feature depicted or described in the resource, or the geographic
location from which the image was captured
position of the creator of the images or. In this case, geographic coordinates may be recorded in field
034 without the presence of a corresponding field 255 in the record."
10/22/21 – Results of MARC Steering Group review - Agreed with the MAC decision.
Discussion Paper 2021-DP03 reviewed use cases for recording geographic coordinates for resources other than cartographic materials. Recording these coordinates can drive geographic positioning interfaces that display data against a map and permit different modes of exploration for users. The January 2021 MAC discussions indicated that it is appropriate to support these applications and that using coordinates recorded in field 034 (Coded Cartographic Mathematical Data) in the Bibliographic or Authority formats is appropriate to provide granular coding that is interpretable by machine.
One view expressed during the MAC discussions is that field 034 can already be applied to record coded geographic coordinates for any type of resource, since it is described as containing "cartographic mathematical data, including scale, projection, and/or coordinates in coded form", but no explicit restriction to cartographic materials is stated. Some libraries did report having implemented field 034 for such use cases in their local systems. However, this view was a minority opinion and several sections of the field and subfield descriptions in this field implicitly assume the data is being recorded for some form of cartographic material. The history of the field, coming as it does from the cartographic materials format prior to format integration, supports this implicit assumption.
Another reason to make the broadening of the usage of the field explicit is that, in accordance with the history and practices related to the field, systems have frequently implemented validation so as to restrict field 034 to records with LDR/06 (Type of Record) values e (Cartographic Material) or f (Manuscript Cartographic Material), which prevents its use for geopositioning data outside of cartographic materials. Since all necessary subfields for recording geographic coordinates are already defined in field 034 in the MARC 21 Bibliographic and Authority formats, the only modifications to the format necessary to fully and unambiguously support these use cases are to the scope and application instructions for field 034.
The linkage between field 034 and field 255 (Cartographic Mathematical Data) in the Bibliographic Format was raised during the January MAC discussions. Some view the link to be so strong that the usage of field 034 cannot be broadened without also broadening field 255 in the same way. (These communities do not hold the contradictory opinion that field 034 is presently broader than field 255.) For cartographic materials, most application profiles for content standards make a strong link between fields 255 and 034 in the Bibliographic format, generally requiring coded coordinates in field 034 supporting a statement of coordinates in field 255. The link made by the application profiles and by some systems is stronger than the dependence enforced by the MARC 21 Bibliographic Format. Currently, the dependence in the format is framed from field 034 towards field 255, in that the use of 034 is optional, but if it is used, there should be a one-to-one correspondence between occurrences of 034 and occurrences of 255. This is stated as follows in the Field Definition and Scope of field 034: "There should be an 034 field corresponding to each 255 field in a record." [italics added]. Further, in the Field Definition and Scope of field 255 it states: “This data may also be coded in field 034 (Coded Mathematical Data)." [italics added]
Field 255 is unambiguously applicable only to cartographic materials, and its Field Definition and Scope describes it as covering "Mathematical data associated with cartographic material, including celestial charts." The linkage made between field 034 and field 255 in many systems results by extension in restricting field 034 to cartographic materials in practice. It is necessary to explicitly broaden field 034 and clarify that in these cases no field 255 is expected, to support a revision of these validation practices.
Discussion Paper 2021-DP03 also mentioned that the existing alternative technique described in field 034 subfield $g to record coordinates using a center point technique could be suitable when the feature being described covers only a small area and the bounding box technique would not be suitable. This technique is already provided for in the format and there is no change proposed. The format's role is to provide a mechanism for encoding the data; determining which technique is to be recommended in a particular case falls instead to the content standards. Best practices for recording coordinates for image materials will evolve and select from these options. There is no need for practices and standards for cartographic materials to be modified in any way.
A final issue discussed was whether a geopositioning application would require that the bibliographic record also contain a separate statement of coordinates formatted in a single string for display, such as is supported in subfield $c in field 255 for cartographic materials. Field 255 is quite intricate and carefully crafted to support current content standards for cartographic materials. Modifying it to support display statements for non-cartographic materials without disrupting any aspect of its current usage would be complex. A requirement for separate display statements was not expressed as an actual need by the requestors; rather, it was discussed during the meeting as a theoretical possibility. From observing geopositioning applications, these applications generally formulate their own end-user coordinate display based on the parsed data used for the pin; a display statement formulated according to ISBD practices stored in a different field would not be relevant. Should other use cases arise that require display statements of mathematical cartographic data for non-cartographic materials, a proposal to expand field 255 or to propose some other solution, could be entertained at a future date.
Satisfying the use case of geopositioning requires the recording of coded geographic coordinates broken out in easily machine-actionable form, as is provided by subfields $d, $e, $f, $g in field 034. An additional statement of coordinates formulated for display only, as is provided in a single subfield $c in field 255 (Cartographic Mathematical Data), is not required for this sort of application. Therefore, this proposal focuses on changes in field 034 of the MARC 21 Bibliographic format, with one change to field 034 in the MARC 21 Authority format, and does not propose any change to Bibliographic field 255.
Proposed additions to the text are underlined, deletions are in strike-out. Only the sections with proposed changes are reproduced below.
Summary: Changes are required in the text for the Field Definition and Scope, indicator 1 value 0, subfield $a, subfield $c, and subfield $g last paragraph. Finally, an additional example illustrating the use of a center point to describe a structure is proposed as the final example under $g.
3.1.1. Revise Field Defintion and Scope:
FIELD DEFINITION AND SCOPE
Contains cartographic mathematical data, including scale, projection, and/or coordinates in coded form. For digital items, the coordinates can represent a bounding rectangle, the outline of the area covered and/or the outline of an interior area not covered. For celestial charts, it may also contain zone, declination data, and/or right ascension data, and/or equinox. For cartographic material,
Tthere should be an 034 field corresponding to each 255 field in a record.
For non-cartographic materials (i.e., images, graphic materials, textual materials, etc.), geographic coordinates are recorded to represent the position of the structure, site or feature depicted or described in the resource, or the position of the creator of the images or graphic materials. In this case, geographic coordinates may be recorded in field 034 without the presence of a corresponding field 255 in the record.
For relief models and other three-dimensional cartographic items, if a single set of scales is used in field 255 (i.e., one horizontal and one vertical scale), the first indicator position in field 034 contains value 1, the denominator of the representative fraction for the horizontal scale is recorded in subfield $b, and the denominator of the representative fraction for the vertical scale is recorded in subfield $c. If multiple or varying sets of scales are recorded as a range, the smaller and larger denominators for the horizontal scales are recorded in the first and second subfield $b respectively, the smaller and larger denominators for the vertical scales are recorded in the first and second subfield $c, respectively, and the first indicator position contains value 3.
3.1.2. Revise Definition of Indicator 1 Value 0:
First Indicator - Type of scale
Specifies the type of scale information given.
0 - Scale indeterminable/No scale recorded
Used when no representative fraction is given in field 255 or no field 255 is present in the record.
3.1.3. Revise Definitions of Subfields $a, $c, $g:
$a - Category of scale
One-character alphabetic code indicating the type of scale of the item.
Used even when a specific scale is not recorded (first indicator position contains value 0). For non-cartographic materials (i.e. images, graphic materials, textual materials, etc.) subfield $a is not used. The codes used in subfield $a are:
$c - Constant ratio linear vertical scale
Denominator of the representative fraction for the vertical scale of relief models and other three-dimensional cartographic items.
$g - Coordinates - southernmost latitude
If the coordinates
for a map or planare given in terms of a center point rather than outside limits, the longitude and latitude which form the central axis are recorded twice (in subfields $d and $e and in $f and $g, respectively).
3.1.4. Add New Example to Subfield $g:
034 0# $dW0735848$eW0735848$fN0404554$gN0404554
[Coordinates of Carnegie Hall, a concert venue depicted in an image]
Summary: An additional example is proposed for subfield $d to illustrate using the center point technique to provide coordinates for a structure that is coded as a corporate body. Changes are required in the last paragraph of subfield $g, to avoid restricting the entity to a geographic entity.
3.2.1. Add New Example to Subfield $d:
$d - Coordinates - westernmost longitude
110 2# $aCarnegie Hall (New York, N.Y.)
034 ## $dW0735848$eW0735848$fN0404554$gN0404554$2wikiped
[Authority record for Carnegie Hall, New York, a concert venue]
3.2.2. Revise Definition of Subfield $g:
$g - Coordinates - southernmost latitude
If the coordinates for an
geographicentity are given in terms of a center point rather than outside limits, the longitude and latitude which form the central axis are recorded twice (in subfields $d and $e and in $f and $g, respectively).
BIBFRAME accommodates the information relating to cartographic materials and if a change to MARC is needed the expectation is that it would not be difficult to accommodate.
In Field 034 (Coded Cartographic Mathematical Data) of the MARC 21 Bibliographic and Authority Formats, make the following changes:
See Section 3.1. for full description of changes.
See Section 3.2. for full description of changes.
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