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Universal Decimal Classification (wikipedia.org)
22 points by harporoeder 9 months ago | hide | past | favorite | 5 comments

I have worked with UDC. Both stacking shelves and cataloguing. Its the peak of classification systems in my biased opinion.

It gives a lot of power in organizing a collection to local needs and specifications. The class numbers can be made ridiculous specific if needed, a good trait for academic collections that can usually be very subject insular. When you get a feel for the system you get an whole other insight when browse shelves. Need to find books about Italian law? Go look where 340-350 is shelved and grab the books with (45) on their back. Upon getting a request from a user, without looking anything up, you can interpret the subjects of the request and often walk right up the books that'll satisfy the user.

That said it takes effort and training to use, and applying it to an existing collection - instead of building one UDC from the start - is a mammoth task no one is willing to waste man hours on. Time is moving on and library classification schemes are a dying tech.

Now we have tagging and full text search, such limiting hierarchies are no longer that useful.

In libraries where the stacks are closed, what would even be the point?

Tags and search lack the orientation given by structured organization. You can complement the structure with them, but you can't replace it. How many times have you searched a word or topic and had to discard dozens of unrelated results? Have you ever wanted to listen to classical music and ended with Beatles music tagged "classic"?

The classification system works, sort of. But...

It comes a moment after going to the library a number of times when you realize that human knowledge is _not_ hierarchical, a tree - it is a graph. And then you understand why it is a monumental task to make the classification to match people's expectations.

You can't map a graph onto a tree.

You are misunderstanding UDC. Faceted classification is precisely not hierarchical.

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