My bad for having chosen an English example. I wasn't aware that over there is parsed as PP. how about

La arbo tie estas granda.
Or
La vojagxo urben estas enua.

How would you Analise these?

bartlett22183:
Not quite. "Over there" in this instance is an idiomatic prepositional phrase (where "there" is acting as an idiomatic demonstrative pronoun and can be the object of a preposition), and in English, at least, prepositional phrases can act as adjectives to modify a noun. I would be interested in what the expert Esperantists have to say on such a matter.

Well, either way, nornen said it better than I did and it is probably less confusing that way. I was trying to think of a way to describe the situation, but couldn't find the proper words.

nornen:La arbo tie estas granda.
Or
La vojagxo urben estas enua.

I'm not a grammarian, but as far as I understood, adverbs modify the meaning of a verb, adjective, other adverb, clause, or sentence.

Your two examples are interesting, but I don't believe these adverbs modify the nouns.

The first sentence is kind of short for:

La arbo, kiu lokiĝas tie, estas granda.

I'm not even sure the 2nd sentence is actually correct. Probably better would be:

La urbovojagxo estas enua.

Are there any experts on this matter that can help clarify? Thanks.

BoriQa, in some languages (e.g. English, German, and Esperanto; not allowed e.g. in Hittite) adverbials (and syntactically adverbs express adverbials) can modify nouns, too.
The examples given above are valid, another one would be "I hit the man with the umbrella" - if I have the umbrella, the adverbial modifies the verb, if he had it - it's an attributive adverbial.

BTW: In La arbo, kiu lokiĝas tie, estas granda the relative sentence modifies a noun, too.

With regard to the original topic: I don't think morfran is right with his semantic division between iom da/kelke da and ioma/kelka. In my opinion e.g. kelke da metroj and kelkaj metroj have the same meaning.

I'm not a grammarian, but as far as I understood, adverbs modify the meaning of a verb, adjective, other adverb, clause, or sentence.

Adverbs in Esperanto can be used quite broadly and may indicate the circumstances (sometimes equivalent to a prepositional phrase). So they can complement a noun.

La libro supre
la arbo tie
la milito, komence de la 13-a jarcento.
la vojaĝo hejmen
inter 10 kaj 12 horoj tage

BoriQa:
I'm not even sure the 2nd sentence is actually correct. Probably better would be:

La urbovojaĝo estas enua.

While I can't speak to the grammatical issue, I can say that I don't think "La urbovojaĝo estas enua" would be better, because it takes away a lot of the meaning. "La vojaĝo urben estas enua" makes the relationship between the trip and the city very clear - it's a trip to the city, as indicated by the ending -en. "Urbovojaĝo" just means "the city trip," and could mean any number of things: a trip to the city, sure, but also trips in the city, trips from the city, trips through the city, etc.

I'm not quite sure whether the original sentence is grammatically correct, either. If I were writing this sentence myself, I would probably say "La vojaĝo al la urbo estas enua," which is grammatically correct but still retains the meaning.

Kirilo81: in some languages (e.g. English, German, and Esperanto; not allowed e.g. in Hittite) adverbials (and syntactically adverbs express adverbials) can modify nouns, too.
The examples given above are valid, another one would be "I hit the man with the umbrella" - if I have the umbrella, the adverbial modifies the verb, if he had it - it's an attributive adverbial.

In English, adverbial phrases do not modify nouns. The example you give, "I hit the man with the umbrella," only contains an adverbial if the prepositional phrase in question in modifying the verb, "hit." If "with the umbrella" is describing how I hit the man, it is an adverbial prepositional phrase. However, if "with the umbrella" is modifying "man," it's not suddenly an adverbial modifying a noun. It's an adjectival prepositional phrase. In English, prepositional phrases can be used as both adjectives and adverbs, and that does not correlate to actual adverbs.

As far as "La arbo, kiu lokiĝas tie, estas granda," it is true that the clause "kiu lokiĝas tie" modifies a noun, "la arbo." Within that phrase, however, the adverb "tie" is modifying the verb, "lokiĝas," which I think is what BoriQa was trying to communicate. Even in the original sentence, "La arbo tie estas granda," the adverb could feasibly be modifying the verb, "estas," with a meaning closer to "The tree is big there." If the sentence is trying to communicate a particular tree, "tie" probably isn't the best word to use. "Tiu arbo" would probably be better, in my opinion.

Thanks everyone for helping me better understand the iom/kelka confusion, as well as the secondary conversation on Adverbs complementing Nouns!!!

Kirilo81:With regard to the original topic: I don't think morfran is right with his semantic division between iom da/kelke da and ioma/kelka. In my opinion e.g. kelke da metroj and kelkaj metroj have the same meaning.

They’re often used interchangeably, I agree. But since BoriQa was asking for the subtle differences, the PIV does make a distinction — not between iom da/kelke da and ioma/kelka, but between the singular and the plural: in the singular, iom da/kelke da and ioma/kelka both indicate a lump sum of something uncountable (ioma libereco “some liberty”), but in the plural they indicate a group of countable things (iomaj liberecoj “some liberties”). So metro probably wouldn’t normally follow ioma/kelka in the singular unless it was regarded as something uncountable, like “metrage”.

PIV:kelka. 1 (in the singular) an indefinite quantity of a whole, who divisions are not expressible by numbers. 2 (in the singular) an indefinite, but definable quantity. SIN. certa. 3 (in the plural) an indefinite quantity of multiple, countable things, in contrast with the whole or with a larger quantity.

bartlett22183:

nornen:

BoriQa:Thanks everybody!
This, in general, is not correct. Adverbs can indeed modify nouns.
For adverb(ial)s of quantity, grade, or measure, your statement might be correct.

Nornen, can you give me an example of an Adverb modifying a noun? Thanks.

The tree over there is an oak.

Not quite. "Over there" in this instance is an idiomatic prepositional phrase (where "there" is acting as an idiomatic demonstrative pronoun and can be the object of a preposition), and in English, at least, prepositional phrases can act as adjectives to modify a noun. I would be interested in what the expert Esperantists have to say on such a matter.

Actually I'd say it's more like an ellipsis of "(which is) over there".

orthohawk:

bartlett22183:

nornen:

BoriQa:Thanks everybody!
This, in general, is not correct. Adverbs can indeed modify nouns.
For adverb(ial)s of quantity, grade, or measure, your statement might be correct.

Nornen, can you give me an example of an Adverb modifying a noun? Thanks.

The tree over there is an oak.

Not quite. "Over there" in this instance is an idiomatic prepositional phrase (where "there" is acting as an idiomatic demonstrative pronoun and can be the object of a preposition), and in English, at least, prepositional phrases can act as adjectives to modify a noun. I would be interested in what the expert Esperantists have to say on such a matter.

Actually I'd say it's more like an ellipsis of "(which is) over there".

Well, along these lines, also "the red ball" could be an ellipsis of "the ball which is red", and adjectives never modify nouns, but are always predicate nouns of invisible subclauses.