Hi Steven,


The comparison tool uses the marc2bibframe2 stylesheet. In marc2bibframe2 the bf:unit/bf:Unit property/class pair aren't used anywhere, which means they aren't in the conversion specifications.


Digging deeper, I checked the 3xx fields mapping and the NumericSubfields conversion specifications. There is an example of bf:unit in 300 – Physical Description in the NumericSubfields document which moves 300$f into a rdfs:label in a bnode connected to bf:unit (w/o the type 'a bf:Unit'; a typo). The 3xx field mappings put $f in a string in the Extent as a display label and don't specify the use of bf:unit/bf:Unit.


Here's the example from the NumericSubfields document w/the types added (also missing a bflc:AppliesTo) and a rdfs:label ("Make a string of all a, f, g and including all repeats of subfields.  Keep in order as in field, insert blank for each subfield code then put this string in rdfs:label").


300 ##$3poems$a1$fpage ;$c108 cm. x 34.5 cm


<instance> bf:extent [ a bf:Extent ;

                       rdfs:label "poems 1 page ; c108 cm. x 34.5 cm";

                       rdf:value "1" ;

                       bf:unit [ a bf:Unit;

                                 rdfs:label "page" ] ;

                       bf:dimensions "108 cm. x 34.5 cm" ;

                       bflc:appliesTo [ a bflc:AppliesTo;

                                        rdfs:label  "poems" ]].


My guess is you also could use this with the contents of $a when you determined somehow it contained a number and a unit (not the hardest regex in the world to write...):

300 ##$a95 linear ft.


<instance> bf:extent [ a bf:Extent ;

                       rdfs:label "95 linear ft.";

                       rdf:value "95";

  bf:unit [ a bf:Unit;

            rdfs:label "linear feet"]].


As you mentioned, the pair are not used in the editing profiles for Bf 2.0.  I don't think we've had anyone ask us to split out the value from the units, but we could implement the second example pretty easily.

Kirk Hess

Library of Congress


From: Bibliographic Framework Transition Initiative Forum [mailto:[log in to unmask]] On Behalf Of Steven Michael Folsom
Sent: Wednesday, November 08, 2017 4:09 PM
To: [log in to unmask]
Subject: [BIBFRAME] bf:unit/bf:Unit and bf:extent/bf:Extent


A quick question I’m hoping LC can clear up…


Can you give an example of how bf:unit/bf:Unit are supposed to be used with bf:extent/bf:Extent? I tried using the BF comparison tool haven’t found an example of bf:unit/bf:Unit being used. I also found no mention of bf:unit/bf:Unit in any of the bfe profiles.



Steven Folsom

Metadata Specialist

Cornell University Library