خريطة المتحف هنا.

Because Arabic often uses nominal sentences in the present tense without a verb meaning to be.

So:

خريطة المتحف هنا
literally follows the pattern:

museum-map + here

In natural English, we say The museum map is here, but in Arabic the is is simply understood.

If you wanted a past-tense version, then Arabic would use a verb, for example:

كانت خريطة المتحف هنا
= The museum map was here

This is because خريطة المتحف is an iḍāfa construction, often called a genitive construction or annexation.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun determines whether the whole phrase is definite or indefinite

So:

• خريطة متحف = a museum map / a map of a museum
• خريطة المتحف = the museum’s map / the map of the museum

Even though خريطة has no الـ, the whole phrase is definite because المتحف is definite.

It is an iḍāfa phrase:

• خريطة = map
• المتحف = the museum

Together:

خريطة المتحف = the map of the museum / the museum map

In this structure:

• the first noun is called المضاف
• the second noun is called المضاف إليه

The second noun is in the genitive case in full formal grammar.

With full case endings, the sentence would be:

خريطةُ المتحفِ هنا

So:

• خريطةُ = nominative, because it is the subject/topic of the sentence
• المتحفِ = genitive, because it is the second part of the iḍāfa

A careful MSA pronunciation is approximately:

kharīṭatu l-matḥafi hunā

A few useful notes:

• خ is a throaty sound, like the ch in Scottish loch or German Bach
• ط is an emphatic t
• ح is a stronger, breathier h from the throat
• هنا is pronounced hunā

In pause, many case endings are dropped, so you will often hear something closer to:

kharīṭat al-matḥaf hunā

That is very normal in actual reading and speech.

Because خريطة ends in ة (tāʾ marbūṭa), and in an iḍāfa construction it is pronounced as t before the next word.

So:

• by itself: خريطة → kharīṭa
• in iḍāfa: خريطة المتحف → kharīṭat al-matḥaf

This is very common:

• مدينة = city
• مدينة القاهرة = the city of Cairo

Here مدينة is pronounced madīnat before القاهرة.

Yes, هنا can appear in different positions depending on emphasis and style.

The sentence you have:

خريطة المتحف هنا
is a very natural way to say The museum map is here.

But Arabic can also say:

هنا خريطة المتحف
which is closer to Here is the museum map or The museum map is here, with a little more focus on here.

So both are possible, but the word order changes the emphasis slightly.

Yes. It is a complete nominal sentence in Arabic.

It has:

• a topic/subject-like element: خريطة المتحف
• a predicate: هنا

So the structure is complete.

Arabic does not need an explicit present-tense to be verb for this kind of sentence.

In full formal grammar, it would be:

خَرِيطَةُ الْمَتْحَفِ هُنَا

More precisely:

• خريطةُ → nominative (-u), because it is the مبتدأ or main noun/topic of the sentence
• المتحفِ → genitive (-i), because it is the second noun in the iḍāfa
• هنا → an adverb of place, and it does not take a normal case ending here

In normal unvocalized writing, these endings are usually omitted.

Yes. In English, those are two different ways to express the same relationship, and Arabic uses the iḍāfa for both.

So خريطة المتحف can be translated as:

• the museum map
• the map of the museum
• sometimes even the museum’s map, depending on context

The exact English wording depends on what sounds most natural in the situation.

Because م is a moon letter, not a sun letter.

In Arabic, the ل in الـ is:

• pronounced clearly before moon letters
• assimilated before sun letters

Since م is a moon letter, you pronounce the l:

المتحف = al-matḥaf

Compare that with a sun-letter example:

الشمس = ash-shams

There the l is not pronounced separately.

Yes. Both خريطة and خارطة are used for map, though خريطة is very common in Modern Standard Arabic.

A learner should recognize both, but خريطة is perfectly standard and very common.

So:

• خريطة المتحف هنا
• خارطة المتحف هنا

Both are understandable, though خريطة is often the safer default for MSA learners.