Overview

Teaching: 10 min
Exercises: 15 min

Questions

Objectives

• What is MARC?

• Where are helpful resource for MARC?

• Understanding the basic structure of a MARC file in pymarc

Episode 2: MARC basics

What is MARC?

“MARC is the acronym for MAchine-Readable Cataloging. It defines a data format that emerged from a Library of Congress-led initiative that began nearly forty years ago. It provides the mechanism by which computers exchange, use, and interpret bibliographic information, and its data elements make up the foundation of most library catalogs used today. MARC became USMARC in the 1980s and MARC 21 in the late 1990s.” https://www.loc.gov/marc/

“MARC Terms and Their Definitions” https://www.loc.gov/marc/umb/um01to06.html#part3

“This online publication provides access to both the full and concise versions of the MARC 21 Format for Bibliographic Data.” http://www.loc.gov/marc/bibliographic/

Reading MARC files with PyMARC

Lets take a look at a marc record, and see what it contains.

Start a new python file episode_2.py and type the following script:

import pymarc

my_marc_file = "NLNZ_example_marc.marc"

reader = pymarc.MARCReader(open(my_marc_file, 'rb'), force_utf8="True") 

for record in reader:
	print (record)
	quit()

You should see a marc record, line-by-line, in the terminal window:

=LDR  00912cam a2200301 a 4500
=001  9962783502836
=003  Nz
=005  20161223124839.0
=008  731001s1967\\\\at\ac\\\\\\\\\00010beng\d
=035  \\$z4260
=035  \\$a(nzNZBN)687856
=035  \\$9   67095940
=035  \\$a(Nz)3760235
=035  \\$a(NLNZils)6278
=035  \\$a(NLNZils)6278-ilsdb
=035  \\$a(OCoLC)957343
=040  \\$dWN*
=042  \\$anznb
=050  0\$aPN5596.B3$bM3
=082  0\$a823.2$220
=100  1\$aManning, Arthur,$d1918-
=245  10$aLarger than life :$bthe story of Eric Baume /$cby Arthur Manning.
=260  \\$aSydney [N.S.W.], :$aWellington [N.Z.] :$bReed,$c1967.
=300  \\$a184 p., [8] p. of plates :$bill., ports. ;$c23 cm.
=500  \\$aEric Baume was a New Zealander.
=600  10$aBaume, Eric,$d1900-1967.
=650  \0$aJournalists$zAustralia$xBiography.
=650  \0$aAuthors, New Zealand$y20th century$xBiography. 

Understanding MARC field in PyMARC

Its useful to understand the structure of the data object we can see, and how it relates to the MARC format.

Notice the first piece of data starts with an =. The first one we see is =LDR. The = tells us its a field label, or tag, and the following 3 characters are the tag value. In this case LDR tells us we’re reading the leader field. All other MARC fields are zero-padded 3 digit numbers. The following data on that row is the field value. In MARC, the first 9 fields are called control fields, and are structured a little differently to all other fields. Its worth referring to the MARC guidelines to make sure we can correctly understand what the data is telling us… http://www.loc.gov/marc/bibliographic/bd00x.html

We’ll get into the details of some of the control fields later on. For now lets focus on one of the “standard” fields and take a look at how its made up. Lets look at the 245 field, the “title statement” http://www.loc.gov/marc/bibliographic/bd245.html

=245  10$aLarger than life :$bthe story of Eric Baume /$cby Arthur Manning.

We’ve established the =245 is telling us the field name. We can see a couple of spaces, and then the digits 1 and 0. These are the two ‘indicators’ for the field. Sometimes they’re empty or blank, sometimes they’re unused (and sometimes encountered as a slash) character. Sometimes they’re set to a value like we can see here. We’ll look at how to parse this information in a moment.

Following the two indicators, we can see some data thats separated by the $ character:

$aLarger than life :$bthe story of Eric Baume /$cby Arthur Manning.

The $ is always followed by another character, the subfield label, and then the value of the subfield. In this instance we can see 3 subfields; a, b, and c:

a| Larger than life :
b| the story of Eric Baume /
c| by Arthur Manning.

Spend a moment looking at the MARC specs for this field, and the data we have in this record.

http://www.loc.gov/marc/bibliographic/bd245.html

Using the MARC standard to “read” a field - indicators

What do the two indicators tell us about the 245 field?

Solution

Indicator 1 is set to the value 1

Looking at the MARC standard for this field, we can see that has the value “1 - Added entry”

Indicator 2 is set to the value 0

Looking at the MARC standard for this field, we can see that has the value “0 - No nonfiling characters”

Using the MARC standard to “read” a field - subfields

What do the three subfields tell us about the 245 field?

Solution

We can see the subfields ‘a’, ‘b’, and ‘c’

Referring to the MARC standard we can see:

“$a - Title”

“Data includes parallel titles, titles subsequent to the first (in items lacking a collective title), and other title information.”

“$b - Remainder of title”

“Data includes parallel titles, titles subsequent to the first (in items lacking a collective title), and other title information.”

“$c - Statement of responsibility, etc.”

“First statement of responsibility and/or remaining data in the field that has not been subfielded by one of the other subfield codes.”

Key Points

• We know where to find resources that describe MARC records/fields

• We know how to identify the component parts of a MARC record/field