A recent comment made it clear that tooling, or the lack thereof, is a real issue for topic maps.
Here is my first suggestion of a tool you can use while authoring a topic map:
Wikipedia.
Seriously, think about it. You want a URL that identifies subject X.
Granting that Wikipedia is a fairly limited set of subjects, it is at least a starting point.
Example: I want a subject identifier for “Donald Duck,” a cartoon character.
I can use the search box at Wikipedia or I can type in a browser:
http://en.wikipedia.org/wiki/Donald%20Duck
Go ahead, try it.
If I don’t know the full name:
http://en.wikipedia.org/wiki/Donald
What do you think?
Allows you to disambiguate Donalds, at least the ones that Wikipedia knows about.
Not to mention giving you access to other subjects and relationships that may be of interest for your topic map.
To include foreign language materials (outside of English only non-thinking zones in the U.S.), try a different language Wikipedia:
http://de.wikipedia.org/wiki/Donald%20Duck
Finding subject identifiers won’t write your topic map for you but can make the job easier.
There are other sources of subject identifiers so send in your suggestions and any syntax short-cuts for accessing them.
You have no doubt read that URIs used as identifiers are supposed to be semi-permanent, “cool,” etc.
But identifiers change over time. It’s one of the reasons for historical semantic diversity.
URIs as identifiers will change as well.
Good thing topic maps enable you to have multiple identifiers for any subject.
Means old references to old identifiers still work.
Glad we dodged having to redo and reproof all those old connections.
Aren’t you?