The Zombie Stack Exchanges That Just Won't Die
I have over 40 books non-fiction books on one shelf. I'd like to be able to sort them in a logical order. I've developed my own way of sorting books by subject that loosely relate to one which start like this:
Computing - Photography - Art - Design - Home Improvement - Gardening ...
This works fine, as I can find any book in seconds regardless of how it's arranged because it's easy to memorise. I do wonder if there are any standards or examples of what I like to call a 'knowledge spectrum'.
Ambo100
Yes. The best known example is the Dewey Decimal System. Librarians call these 'classification systems', and as you've noticed, they tend to group items physically near each other when their subject matter is related. For larger libraries, this benefit helps users serendipitously discover books on their topics of interest without knowing the books' titles beforehand.
The Dewey Decimal Classification (DDC) is only the best known example of a classification system. Actually your own system is also a classification if you put subject separators somewhere in between. In addition to DDC there are many classifications, also for small collections. Library scientists have also created more elaborated systems, such as facetted classifications and thesauri, which allow for searching in multiple dimensions. But if you want a strict logical order, a classification is the best you can get, despite its main drawback: each topic and each book can only have one place. The general form of a classification is like the outline of a book with chapters, sections, subsections etc. Obviously there are many possible ways to structure a book.
If you are looking for an existing classification, you should first think about whether you want to sort the books in your collection (specialized classification) or all possible books in general (universal classification). Questions on classification systems are related to knowledge organization and to philosophy of science.
One of the basic principles of any classification system is helping the user find what they want. If you're the only (or principle) user of the collection, you can use any system you like that works for you. Looking at Dewey, or Library of Congress, or other systems might give you inspiration, of course.
Personally, while I'm happy to use those systems in my professional life, they don't fit my personal library at all - I have large numbers of books in areas both LOC and Dewey handle quite badly (religion that isn't Christianity, mythology, the use of technology tools). So I sort these sections in an order that makes sense for me. And within fiction, I prefer to browse and therefore sort by very specific sub-genre (urban fantasy, historical mystery, etc.)
The other part has to do with the practical realities of space use: if I have 5 shelves worth of a general subject, I'm going to store those somewhere I have space for those five shelves, even if logically, they might fit better between one topic and another. Or I might choose to store those books in the room where I use them a lot. Home use has considerations a public space doesn't.
One informal option for managing a collection is using a catalog (I use LibraryThing, but there are plenty of others) that will let you tag with different topics - that way, it's easy (once I set the tags) to browse a list of items about a particular subject even if they might be shelved in varied places for other reasons (size, where I'm most likely to want to use them.)
The thing about libraries is that there are lots of patrons and librarians -- you use a well established classification system so that others can make sense of the organization, and can more quickly find particular items of interest.
If you have a system that works for you, there's absolutely no reason to change. Personally, I organize my books at home by:
* Cookbooks
* Cookbooks, personal favorites (kept just outside the kitchen)
* Cookbooks, incoming (ones I haven't read yet)
* Cookbooks, oversized
* Cookbooks, historical
* Cookbooks, community
* Cookbooks, general
* Oversized, non-cookbooks
* Gardening
* DIY / Home Improvement
* Architecture
* IT / Programming
* Comics
* Fiction
* Everything else
The only reason for the oversized sections are for density. Most of the cookbooks are actually sorted by height rather than topic. (I just have 2.5 bookcases of cookbooks, so it's not as obvious)