My bad in (2) that should have been 781 and it’s LC’s way to indicate the geographic form used for a 181 when a heading may be geographically subdivided. The point is, when you are trying to do authority matching/mapping you have to match against the 181’s in LCSH *and* the 781’s in NAF. This is an oddity of the LC authority file that people may not be aware of, hence why I pointed it out. As I indicated, in my mapping projects I have taken LCSH and added new 181 records based on the 781’s found in NAF. This allows the matching process to work reasonably well without dragging in the entire NAF for searching and matching. However, this still doesn’t give the complete the picture since in LCSH the *construction rules* allow you to use things in the name authority file as subjects, ugh. Effectively, LCSH isn’t useful by itself when trying to match/decompose 6XX in bibliographic records. You really need access to NAF as well. Things get worst when talking about the Children’s headings… since you can pull from both LCSH and NAF, ugh-ugh. While LC would like us to think of the authority file as three separate authorities, LCSH, LCSHac, NAF, in reality the dependencies require you to ignore the thesaurus boundaries and just treat the entire authority file as one thesauri. We struggled with this in the terminology services project, especially when the references in one thesaurus cross over into the other thesauri. Andy. From: Ya'aqov Ziso [mailto:[log in to unmask]] Sent: Thursday, April 07, 2011 13:47 To: Code for Libraries; Houghton,Andrew Cc: Hickey,Thom; LeVan,Ralph Subject: Re: [CODE4LIB] LCSH and Linked Data Andrew, as always, most helpful news, kindest thanks! more [YZ] below: 1. No disagreement, except that some 151 appears in the name file and some appear in the subject file: n82068148 008/11=a 008/14=a 151 _ _ $a England sh2010015057 008/11=a 008/14=b 151 _ _ $a Tabasco Mountains (Mexico) [YZ] would it be possible then to use both files as sources and create one file for geographical names for our purpose(s)? 2. Yes, see n50000359 151 _ _ $a Sonora (Mexico : State) 751 _ _ $z Mexico $z Sonora (State) [YZ] Both stand for a distinct cataloging usage. Jonathan's suggestion to consult LC may answer the question of which field/when to use for geographical names 3. Oops, my apologies to my VIAF colleagues, I believe that geographic names are in the works… [YZ] inshAllah! 4. That is probably correct. England may appear as both a 110 *and* a 151 because the 110 signifies the concept for the country entity while the 151 signifies the concept for the geographic place. A subtle distinction... [YZ] Exactly. This distinction called for creating both a 110 AND a 151. But we are talking about 151. The case where there is both a 110 and a 151 does NOT apply to geographic names, only to some. [YZ] VIAF would be helpful to provide a way to limit geographical names ONLY to 151 names and their cross references.