Vexillology

If you see a red flag with a white thingy in the middle in Hamburg, you can be fairly certain it’ll be the flag of Hamburg. And if it ends up being another flag, why would that be a huge issue, anyway? In daily life nothing really depends on being able to recognise the flag from large distances.

In any case, a flag is a symbol representing some abstract concept. If the inhabitants of a city know their city’s flag is a red field with a white tower, it doesn’t matter when they can’t literally discern the white tower on the red flag flying atop city hall. Even without being able to physically see the tower, they can still see it because they know what the white blob is supposed to be.

Beside this, flags are used in many more ways than just from flagpoles. They are used in printing, in digital media, generally as decoration. In all these cases the ‘recognisability from far away’ criterium isn’t (as) relevant.