What is the adjective meaning "great in area"?

We have

• length → long
• volume → voluminous

But what is the corresponding adjective for "area"?

I've found "areal", but it seems that this means "pertaining to an area", rather than "having area" or "great in area".

Expanse: the area of something; a large and usually flat open space or area

Expansive: covering a large space or area

Length → Long
Volume → Voluminous
Expanse → Expansive

There is a technical sense of the word "extensive" that describes quantity of area. It is sometimes used to mean "quantity" in general, but it always has a connotative meaning that implies coverage of an area (whether spatial or abstract).

I think I would say spacious.

How long is the string? How voluminous is the box? How spacious is the garden/living room/car park etc?