Learn French: Tu as un plan de la ville ? - Do you have a map of the city?

In French, un plan is typically used for a detailed map of a city, town, or neighborhood. Une carte is used for larger geographical areas, like a country or the world (e.g., une carte de France).

There is no question phrase here like est-ce que. How do we know it is a question?

In spoken, everyday French, you can turn a regular statement (Tu as, meaning "You have") into a question just by making the pitch of your voice go up at the end. You could also say Est-ce que tu as un plan de la ville ? to mean the exact same thing.

Why is it de la ville and not just de ville?

De la translates to "of the" for feminine nouns like ville (city). If the noun were masculine, like village, the words de and le would combine into the single word du (for example, un plan du village).

How would I ask where the map is, using the word où from this lesson?

You can use où (where) with the verb est (is). To ask "Where is the map of the city?", you would simply say Où est le plan de la ville ?