Tag of the Month

Category: Tag of the Month Bibliographic Archives
Title: 255 - Cartographic Mathematical Data (R)

Mathematical data information is used with 
cartographic materials to assist in determining scale, 
projection, and could contain coordinates and equinox. 
In the MARC record this information is entered into 
the 255 tag and is a required field for cartographic 
material. Cartographic materials will include such 
items as maps, atlases, and globes or other items that 
represent the whole or part of the earth or any 
celestial body. 

Chapter 3 of AACR2 covers creation of cartographic 
materials and Rule 3.3 deals specifically with the 
mathematical data area of the record. The statement of 
scale (Rule 3.3B) is given as a representative 
fraction expressed as a ratio (1:x). The statement of 
projection (Rule 3.3C) is entered if it appears on the 
item. Statement of coordinates and equinox is entered 
if available (Rule 3.3D), entry of this information is 

RDA guideline 7.25.1 gives basic instructions on recording
scale. Scale is recorded as a representative fraction
expressed as a ratio ( Projection is recorded if
considered important for identification ( Guidelines
on recording the coordinates of cartographic content 
(longitude and latitude) are given in (  When
coordinates for celestial cartographic content are recorded,
a statement of equinox is also recorded as a year (

Subfield a will contain the statement of scale as it 
appears on the item. Begin the subfield with the word 
Scale followed by the scale ratio. When calculating 
the scale information that does not appear on the 
item, enter the resulting ratio in brackets. When no 
information on the scale is given, enter Scale not 
given in subfield a. 

Subfield b contains the entire statement of projection 
found on the item. Use the abbreviation of proj. for 

Subfield c contains the statement of coordinates in 
the order of the westernmost longitude, easternmost
longitude, northernmost latitude, and southernmost 
latitude. This information is always enclosed in 
parentheses with the longitude and latitude 
information separated by a slash. Each longitude 
statement and each latitude statement is separated by 
two hyphens. 

Subfields d and e are used with celestial charts. 
Information on right ascension (RA), declination 
(Decl.), or zones goes into subfield d. The 
information on right ascension and declination is 
separated by a slash. When two right ascensions are 
found, give both separated by the word "to". 

Subfield e contains the equinox as a year preceded by 


First  Undefined

 blank Undefined

Second  Undefined

 blank Undefined


     a Statement of scale (NR) 

     b Statement of projection (NR) 

     c Statement of coordinates (NR) 

     d Statement of zone (NR) 

     e Statement of equinox (NR) 


Subfields d and e are separated by a space semicolon. 

Data in subfields c, d, and e is enclosed in 

The tag ends in a period.


     255    _aScale 1:7,500,000.

     255    _aScale not given.

     255    _aScale varies.

     255    _aScale [ca. 1:13,835,000]. 1 cm. = 138 
              km. 1 in. = 218 miles ;
            _bChamberlin trimetric proj.

     255    _a1:250,000
            _c(E 32(30'--E34(30'/N35(30'--N 35(00').

     255    _aScale 88 mm per 1(
            _d(RA 16 hr./Decl. +30( ;
            _eeq. 1973).

     255    _aScales vary
            _d(Zones +90( to +81( to 63(, -81( to 98( ;
            _eeq. 1950).

     255    _aScales vary
            _e(eq. 1986).