Legal?
Exeng, what you describe is a "contact approach," not a "visual approach." It's actually illegal not to have and keep the runway in sight for a visual, not that we might get too exercised about that, no.
I used to do "contact approaches" in the USA, but in Nigeria I had to call "runway in sight" to be cleared for a visual, and the rules require that one keeps the runway in sight. So, not "legal" at all, what you describe doing....
There was a rather high profile accident in North Carolina when a 727 crew knew exactly where they were, using known points on the ground, particularly a prominent road. It turned out to be the wrong road, and 727s aren't much use for off-airport landings. That's the trouble with a contact approach, the pilot depending on what he knows.
I remember wondering what that big tree was doing in the middle of a dirt strip up in northern Nigeria, during harmattan. Well, it was the middle of the village, not far from the strip and on the same alignment, wasn't it? I was quite sure I knew where I was, and I wasn't very far off, maybe a half-mile or so. I did have the required visibility of one mile: a half-mile left plus a half-mile right, right?