What are the details in this UML instance?

Question

So far these are the assumptions made, correct these assumptions if they are wrong.

• A Mountain can have to 0 to Many classifications (Not sure if it's the converse)
• 0 to Many Mountains have 0 to Many Routes
• A Route has 0 to Many Parties
• 0 to Many Parties have 1..6 walkers (Don't quite get this one)
• 0 to Many Parties have a guide
• A Guide can have 0 to Many Qualifications (Seems odd)

Answer 1

I see 2 issues with your interpretation:

1. You interpret the multiplicity in a too direct way. Remember, UML is supposed to help to understand, not to obfuscate.
2. The are several mistakes in your interpretation. In general, a 2-way relation can be translated to one or two sensible statements: X [m..n]---[k..l] Y will be read like this:

X uses/addresses/utilizes/depends/etc. on k..l Y's

Y uses/addresses/utilizes/depends/etc. on m..n X's

I would translate your diagram to the following statements:

• A classification can apply to any number of mountains and each mountain has a qualification
• A mountain can be crossed by an arbitrary amount of routes and route can pass through an arbitrary amount of mountains
• A route can be traveled by multiple parties and each party travels a specific single route
• A party consists of 1 to 6 walkers and a walker can participate in any number of parties
• A party is linked to a guide and a guide can be in charge of several parties
• A qualification can apply to an arbitrary number of guides and each guide has a single qualification

Answer 2

First, let me make it clear that this diagram is showing classes, not instances. Second, this diagram is missing some association-end names, multiplicities, and navigabilities. Third, some of your bullets are backwards. Are you by chance trying to read the association ends clockwise? (There are some notations, or at least people, who do that, and it's not a good idea.)

I just scanned the UML spec to remind myself of what the default is for an unspecified association-end multiplicity and I couldn't find it. I think I remember it being [1..1], but it's been years since I came across that information in an offhand conversation with one of the XMI experts at the OMG. That's a great reason to always specify what it is! The default for an attribute is [1..1], so an association end default is probably the same.

A multiplicity and association-end name belongs next to its property's type, so, for example, your bullet:

• A Mountain can have to 0 to Many classifications (Not sure if it's the converse)

should be either: "a Classification can classify many Mountains" or "a Mountain is classified by one Classification". It would be clearer if the diagram showed that you cannot navigate from a Classification to a Mountain (or used the new "dot notation" to show that Classification does not own a property of type Mountain).

Your bullet:

• 0 to Many Parties have 1..6 walkers

is also incorrect. Each line should only describe one direction, not both directions. That bullet should be split into "A Party comprises 1 to 6 Walkers" and "A Walker may participate in multiple Partys". Those two lines make a lot more sense.

I won't correct all of the bullets for you. Hopefully you get the gist.