What does Otherwise deserted mean?

See a translation

“Otherwise deserted” means that besides the subject, the setting mentioned is deserted




Otherwise (___)
If (___) is an adjective, then that means everything except the subject is (___)


For example:
They stayed in the otherwise deserted building.

In this case, if they (subject) weren’t in the building, the building would be completely deserted (adjective).



Another example:
There was a light colored dot on the otherwise dark screen

“Dark” is the adjective,so:
Everything on the screen expect the light colored dot (subject) is dark (adjective)