Reiseformålet oppgis uavhengig av om reiseruten er kort.

Reiseformålet is a compound noun:

• reise = travel / trip
• formål = purpose

So reiseformål means travel purpose or purpose of the trip. Norwegian uses compound nouns much more freely than English, so where English often prefers the purpose of the trip, Norwegian often packs that into one word.

Because Norwegian usually puts the definite article at the end of the noun instead of using a separate word in front.

Here:

• formål = purpose
• formålet = the purpose

Since this is a compound noun, the definite ending goes on the last part:

• reiseformål = travel purpose
• reiseformålet = the travel purpose / the purpose of the trip

So the meaning of the is already built into -et.

The main noun in the compound is formål, which is a neuter noun. In the definite singular, many neuter nouns take -et.

So:

• et formål = a purpose
• formålet = the purpose

That same definite ending appears in the whole compound: reiseformålet.

Oppgis is the present passive form of oppgi, which can mean:

• state
• give
• specify
• provide

In this sentence, oppgis means something like is stated, is given, or must be provided, depending on context.

This verb is very common in formal writing, especially in forms, applications, and official instructions.

Yes. It is an s-passive form, which is very common in Norwegian.

• å oppgi = to state / provide
• oppgis = is stated / is provided

So Reiseformålet oppgis means The purpose of the trip is stated/provided.

This kind of passive often sounds more official or impersonal than a sentence with man or du.

Uavhengig av means regardless of, independent of, or irrespective of.

It is a fixed expression:

• uavhengig = independent
• av = of

So uavhengig av om ... means regardless of whether ...

Here om means whether, not a real conditional if.

The phrase uavhengig av om is the natural way to say regardless of whether.

So:

• uavhengig av om reiseruten er kort = regardless of whether the route is short

You would not normally use hvis here, because hvis is more clearly conditional: if.

Reiseruten is another compound noun:

• reise = travel / trip
• rute = route

So reiserute means travel route, route, or sometimes itinerary depending on context.

Then -en makes it definite:

• en reiserute = a route / an itinerary
• reiseruten = the route / the itinerary

Because om reiseruten er kort is a subordinate clause, and subordinate clauses do not use the normal main-clause verb-second pattern.

Compare:

• Main clause: Reiseruten er kort.
• Subordinate clause: ... om reiseruten er kort

After a subordinating word like om, the subject usually comes before the verb.

So:

• om reiseruten er kort = correct
• om er reiseruten kort = not correct here

Because it is used predicatively, after er:

• reiseruten er kort = the route is short

In predicative position, adjectives do not take a definite ending. Also, kort is one of those adjectives whose singular forms look the same.

For example:

• en kort rute = a short route
• ruten er kort = the route is short
• korte ruter = short routes
• rutene er korte = the routes are short

So in this sentence, kort is exactly the form you would expect.

Yes, absolutely.

• Reiseformålet oppgis ...
• Formålet med reisen oppgis ...

Both are possible and mean nearly the same thing.

The version with the compound noun, reiseformålet, is more compact and feels especially natural in formal or administrative Norwegian. The version with formålet med reisen is a bit more expanded and may feel slightly more transparent to a learner.

It sounds fairly formal and administrative. It feels like something you might read:

• on a form
• in travel regulations
• in an application process
• in official instructions

In everyday speech, a person might say something more direct, such as:

• Du må oppgi hvorfor du reiser, selv om ruten er kort.
• Du må si hva formålet med reisen er, selv om turen er kort.

So the original sentence is correct and natural, but it belongs more to formal written style.

Because Norwegian normally does not put a comma before a subordinate clause that follows the main clause in a sentence like this.

So this is standard:

• Reiseformålet oppgis uavhengig av om reiseruten er kort.

That is normal Norwegian punctuation.