X51 Geographic Names - General Information

Field definition and scope:

Each geographic name field is unique in its definition and scope. For specific information, select from the list below.

451 See From Tracing - Geographic Name (R)

751 Established Heading Linking Entry - Geographic Name (R)

Record requirements: The National level record requirement for the geographic name fields is Mandatory if applicable, except for field 751 which is Optional. For the national level requirements by subfield, see the specific field.

Field repeatability: See the specific field for its repeatability.

Guidelines for applying content designators:

The content designators identify the subelements occurring in geographic name headings constructed according to generally accepted cataloging and thesaurus-building conventions [e.g., Anglo-American Cataloguing Rules (AACR 2), Library of Congress Subject Headings (LCSH)].

Jurisdiction names (including those that are ecclesiastical entities) alone or followed by subject subdivisions are X51 geographic names.

A corporate name, a form subheading, a title of a work, and/or a city section name entered under the name of a jurisdiction are contained in the X10 fields.

Geographic names used in phrase subject headings (e.g., Iran in the Koran) are contained in the X50 fields.

A geographic name that is authorized for use only as a subject subdivision part of an extended subject heading is contained in a 181 (Heading - Geographic Subdivision) field.

The indicators, subfield codes, and input conventions for the geographic name fields 151, 451, 551, and 751 follow similar patterns. Guidelines for applying them are below. Subfields are grouped by type of entry.

For indicator and subfield code definitions and examples, National level (NLR) record requirements, and designator repeatability, see table below. An asterisk ( * ) in the column indicates that the requirement varies. See table in the specific field.:

Position	Description	NLR	Repeatability
Field X51	Geographic Names	*	*
Indicator:
First	Undefined; contains a blank	M

Second
151, 451, 551	Undefined; contains a blank	M

751	Thesaurus	M
0	Library of Congress Subject Headings/Name authority file	A
1	LC subject headings for children's literature	A
2	Medical Subject Headings/NLM name authority file	A
3	National Agricultural Library subject authority file	A
4	Source not specified	A
5	Canadian Subject Headings/LAC name authority file	A
6	Répertoire de vedettes-matière	A
7	Source specified in subfield $2	A

Subfield code:
	Name portion
$a	Geographic name	M	NR
$g	Miscellaneous information	A	R

	Subject subdivision portion
$v	Form subdivision	A	R
$x	General subdivision	A	R
$y	Chronological subdivision	A	R
$z	Geographic subdivision	A	R

	Tracing and linking subfields
$i	Relationship information [451, 551, 751]	current - A earlier - A	R
$w	Control subfield [451, 551, 751]	A	NR
$0	Authority record control number or standard number [551, 751]	A	R
$1	Real World Object URI [551, 751]		R
$2	Source of heading or term [751]	A	NR
$4	Relationship [451, 551, 751]	O	R
$5	Institution to which field applies [451, 551, 751]	A	R
$6	Linkage	A	NR
$8	Field link and sequence number	O	R

Input conventions:

Ambiguous headings (what is considered a "geographic" name)

Punctuation

Spacing

Display constant for X51 fields

Content designator history:

Second Indicator - Nonfiling characters [151, 451, 551] [obsolete]: The second indicator position was made obsolete in fields 151, 451, and 551 in 1993. The values were: 0-9 (Number of nonfiling characters present).

Subfield $b - Name following place as entry element [151, 451, 551] [obsolete]: Subfield $b was made obsolete in fields 151, 451, and 551 in 1987. A city section name entered under the name of a jurisdiction is contained in an X10 field. Records created before this change may contain an X51 field with a subfield $b for this type of name.

Subfield $g - Miscellaneous information [new, 2014]

Subfield $i - Reference instruction phrase [451, 551] [redefined, 2009]

Subfield $i - Relationship information [751] [new, 2014]

Subfields $u - Record control number [751] [obsolete, 1997] [USMARC only]

$v - Record control number [751] [redefined, 1995] [USMARC only]

$0 - Record control number [551, 751] [new, 1997]

$0 - Record control number [551, 751] [redefined, 2010]

$v - Form subdivision [redefined, 1995]

$3 - Authority record control number [obsolete, 1997] [CAN/MARC only]

In USMARC, from 1993 to 1995, subfield $v was defined as Record control number in the 7XX Heading Linking Entry fields. When subfield $v was adapted for form subdivisions in MARC bibliographic and authority heading fields in 1995, subfield $v was redefined as Form subdivision and subfield $u was defined as Record control number. In 1997, subfield $0 was added as Record control number in 5XX and 7XX fields and $u was made obsolete.

Subfield $1 - Real World Object URI [551, 751] [new, 2017]

Subfield $4 - Relationship code [451, 551] [new, 2009]

Subfield $4 - Relationship code [751] [new, 2014]

Subfield $4 - Relationship code [451, 551, 751] [renamed, 2017] [redescribed, 2017]: Subfield $4 was renamed to Relationship and redescribed to allow for the recording of relationship URIs in addition to MARC and non-MARC codes.