Oznakowanie jest jasne, a znak szlaku dobrze widać.

Oznakowanie means marking, signage, or the system of signs/markers. In this sentence, it refers to the overall trail marking or waymarking, not just one single sign.

So:

• oznakowanie = the marking/signage as a whole
• znak = one individual sign or marker

That is why both words appear in the same sentence: one talks about the overall marking system, and the other talks about a specific trail sign.

Because oznakowanie is a neuter singular noun, the adjective has to agree with it.

Agreement in Polish means the adjective changes form to match the noun’s:

• gender
• number
• case

Here:

• oznakowanie = neuter singular
• so jasny becomes jasne

Compare:

• jasny znak = a clear/bright sign
• jasna droga = a clear road
• jasne oznakowanie = clear signage

Polish often omits to be in the past and future less often, but in the present tense with predicate adjectives like this, jest is normally used.

So:

• Oznakowanie jest jasne = The signage is clear

You would not normally say just Oznakowanie jasne in standard neutral Polish. That sounds incomplete in most contexts.

Polish does omit to be in some other sentence types, especially with identity statements in colloquial speech, but here jest is the normal choice.

Here a works a lot like and, but it often has a slight sense of while, whereas, or and at the same time.

So:

• Oznakowanie jest jasne, a znak szlaku dobrze widać.

means something like:

• The signage is clear, and the trail marker is easy to see.

In many sentences, a links two related statements more loosely than i would.

Very roughly:

• i = and, simple addition
• a = and/but/while, linking or contrasting two facts

In this sentence, a sounds very natural because the second part adds another observation about visibility.

Szlaku is the genitive singular form of szlak.

The phrase znak szlaku literally means:

• sign of the trail
• more naturally in English: trail sign or trail marker

This is a very common Polish structure:

• X + noun in the genitive = X of Y

Examples:

• kolor samochodu = the color of the car
• koniec dnia = the end of the day
• znak szlaku = the sign/marker of the trail

So szlaku is not the subject here; it depends on znak.

Widać is a very common impersonal form in Polish. It means something like:

• one can see
• it is visible
• it can be seen

So:

• znak szlaku dobrze widać

literally is closer to:

• the trail marker is well visible
• one can see the trail marker well

This structure is very natural in Polish when talking about visibility in a general way, without saying exactly who sees it.

Compare:

• Widzę znak. = I see the sign.
• Widać znak. = The sign is visible / You can see the sign.

Both are possible, but they are slightly different in style.

• znak szlaku dobrze widać = the trail marker is easy to see / you can see it well
• znak szlaku jest dobrze widoczny = the trail marker is clearly visible

The version with widać is very natural and common in everyday Polish. It focuses on the practical fact of visibility.

The version with widoczny is also correct, but it sounds a bit more descriptive or formal.

So the sentence uses a very idiomatic Polish way to talk about visibility.

It is dobrze because it modifies the verb-like expression widać, so Polish uses an adverb, not an adjective.

• dobrze = well
• widać = can be seen / is visible

So:

• dobrze widać = can be seen well / is clearly visible

If you used an adjective, it would need a different structure, for example:

• znak jest dobrze widoczny

Here:

• dobrze = adverb
• widoczny = adjective

Both are grammatical, but in the original sentence dobrze correctly modifies widać.

Here it means clear, not just bright.

The adjective jasny/jasna/jasne can mean different things depending on context:

• bright/light-colored
• clear/easy to understand

In:

• Oznakowanie jest jasne

the intended meaning is that the signage is clear, easy to understand, or unambiguous.

So this is about clarity of marking, not only about color or brightness.

The basic idea is:

• znak szlaku = the trail marker
• dobrze = well
• widać = is visible / can be seen

Polish word order is flexible, but this order sounds natural and neutral enough in context.

You could also hear:

• Dobrze widać znak szlaku.

That version often feels slightly more natural if you want to emphasize the visibility itself first.

Because Polish uses cases, word order is freer than in English, but different orders can shift emphasis.

Yes. Widać is closely related to widzieć (to see).

• widzieć = to see
• widać = it is visible / one can see

They belong to the same word family:

• widzę = I see
• widzisz = you see
• widać = can be seen / is visible
• widoczny = visible
• widok = view

For learners, it is useful to remember widać as a fixed common expression rather than trying to force it into the same pattern as ordinary personal verb forms.