For #1, you need what you asked for, probably, if you want the subject 
headings to be consistent with other LCSH on the rest of your records.

For #2, you can provide a useful topical/subject type heading via much 
simpler and more feasible solutions than mapping to LCSH.  For #2, you 
don't need a map to LCSH, you need the LCC schedules with descriptions 
of what each range of LCC call numbers is for, in machine-readable form. 
(Along wtih an algorithm to determine if a call number is in a range of 
LCC call numbers, which is trickier than you might originally think 
becuase LCC call numbers sort oddly).   If you are interested in that 
approach, it's a different question, which no doubt some people on this 
list can provide tips for.

> Thanks everybody!
>
> this is useful for a couple of purposes
> 1) sometimes we have records that have call numbers, but no subject headings.
> this would be useful to provide those.
> 2) i'm thinking of providing a 'subject heading' label to our shelf browser --
> so users see, in addition to the callnumber -- what the call number means.
>
> thanks again!
> rick
>
>
>
> On Tue, Oct 18, 2011 at 2:33 PM, Jonathan Rochkind<[log in to unmask]>  wrote:
>> Anyone know if the OCLC Terminology Service provides such a mapping? The
>> Terminology Service may be free if you are already an OCLC cataloging
>> member.
>>
>> At one point I think I saw an absolutely free open access machine readable
>> mapping somewhere, that was made at some point in the past and no longer
>> updated... but I cant' remember where I saw that even.
>>
>>> LC's Classification Web provides a mapping from LC classifications to
>>> LC subject headings.  There is a manual web interface, used mainly by
>>> catalogers, which requires a subscription:
>>>      http://classificationweb.net/
>>>
>>> I don't know if it has any kind of API.
>>>
>>> Keith
>>>
>>>
>>> On Tue, Oct 18, 2011 at 2:11 PM, Enrico Silterra<[log in to unmask]>
>>>   wrote:
>>>> is there any way to go from a LC call number,
>>>> like DF853  to http://id.loc.gov/authorities/subjects/sh85057107
>>>> via some sort of api? opensearch?
>>>> thanks,
>>>> rick
>>>>
>>>>
>>>>
>>>> --
>>>> Enrico Silterra Software Engineer
>>>> 501 Olin Library Cornell University Ithaca NY 14853
>>>> Voice: 607-255-6851 Fax:     607-255-6110 E-mail: [log in to unmask]
>>>> http://www.library.cornell.edu/dlit
>>>> "Out of the crooked timber of humanity no straight thing was ever made"
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>
>