Understanding MARC 21 Maps
MARC Maps dictate the tags and subfields from which data is extracted into Portfolio. The default MARC 21 Maps are included in a table (see, Delivered MARC 21 MARC Maps) so you can see how Portfolio extracts data to place in search fields.
Portfolio includes over 100 MARC Maps to various MARC 21 tags and subfields. The following table describes the contents in each column of the Delivered MARC 21 Maps:
| Column | Descritpion |
|---|---|
|
MARC Map Name |
Displays the name of the MARC Map as recorded in Portfolio. |
|
Entry Code |
Displays the unique identifier of the MARC Map as recorded in Portfolio. |
|
MARC Map Condition |
Lists the condition script used to determine if information is extracted from the record. For more information, see Writing a MARC Map condition. This condition is used for the entire MARC Map. Other conditions may be on the Tag level. |
|
Tag |
Lists each of the tags from which the MARC Map extracts data from the MARC record. |
|
Tag Condition |
Lists the condition script used to determine if information is extracted from the tag. For more information, see Writing a MARC Map condition. |
|
Subfields |
Lists each of the subfields from which data is extracted from the MARC record. Subfields are indicated by their letter or numeral. If the tag does not have subfields defined, an underscore "_" indicates the entire field. If the MARC Map extracts a substring of the data in a subfield, the table indicates that by including the start position (x) and length (y) in brackets (for example, "[x,y]"). The start position is base zero, meaning that the first character starts at "0", so "[0,1]" extracts the first character in the tag. To indicate the field and substring, this would be displayed as, for example "a[0,1]" (first character in tag a) or "_[0,2]" (the first two characters in tag field). |
To understand how MARC Maps work, it can help to have a MARC record to refer to. The following record is compiled using the MARC 21 format.
Leader/00-23 *****nam##22*****#a#4500
001 <control number>
003 <control number identifier>
005 19920331092212.7
007/00-01 ta
008/00-39 820305s1991####nyu###########001#0#eng##
020 ##$a0845348116 :$c$29.95 (£19.50 U.K.)
020 ##$a0845348205 (pbk.)
040 ##$a[organization code]$c[organization code]
050 14$aPN1992.8.S4$bT47 1991
082 04$a791.45/75/0973$219
100 1#$aTerrace, Vincent,$d1948-
245 10$aFifty years of television :$ba guide to series and pilots, 1937-1988 /$cVincent Terrace.
246 1#$a50 years of television
260 ##$aNew York :$bCornwall Books,$cc1991.
300 ##$a864 p. ;$c24 cm.
500 ##$aIncludes index.
650 #0$aTelevision pilot programs$zUnited States$vCatalogs.
650 #0$aTelevision serials$zUnited States$vCatalogs.
700 1#$aTerrace, Vincent.
The MARC Maps will extract the needed information according to the tags and subfields listed.
Rather than examining each MARC Map, the following table lists three common and simple MARC 21 Maps that demonstrate some MARC Map basics.
| MARC Map Name | Entry Code | Tag | Subfield(s) |
|---|---|---|---|
|
Author |
AUTHOR |
100 |
a, b, c, d, e, f, j, k, l, m, n, o, p, q, r, s, t, 0 |
|
|
|
110 |
a, b, c, d, e, f, k, l, m, n, o, p, r, s, t, 0 |
|
|
|
111 |
a, c, d, e, f, j, k, l, n, p, q, s, t, 0 |
|
|
|
700 |
a, b, c, d, e, f, i, j, k, l, m, n, o, p, q, r, s, t, 0 |
|
|
|
710 |
a, b, c, d, e, f, i, k, l, m, n, o, p, r, s, t, 0 |
|
|
|
711 |
a, c, d, e, f, i, j, k, l, n, p, s, t, 0 |
|
Title |
DSP_TITLE |
245 |
a, b, c, f, g, h, k, n, p, s |
|
Subject Term |
DSP_SUBJECT_TERM |
650 |
a, ( -- )b(), ( -- )c(), ( -- )d(), ( -- )v(), ( -- )x(), ( -- )y(), ( -- )z(), ( -- )0(), ( -- )3(), ( -- )4() |
In the table, the "MARC Map Name" and "Entry Code" are used to identify the MARC Map in Portfolio. "MARC Map Condition" and "Tag Condition" would display any conditions controlling the extraction of data on the MARC Map and Tag Map level. "Tag" indicates the tag from which data is extracted, and "Subfield(s)" indicates one or more subfields from which the data is extracted; it also displays any characters (punctuation or other constants) that would be inserted before and after the extracted string (inside but not including the parentheses).
The table below displays what data each of the listed default MARC Maps extract from the sample MARC record.
| Map | Result |
|---|---|
|
Author |
Terrace, Vincent, 1948- |
|
Title |
Fifty years of television : a guide to series and pilots, 1937-1988/ Vincent Terrace. |
|
Subject Term |
Television pilot programs -- United States -- Catalogs. Television serials -- United States -- Catalogs. |