Even a chart plotter can sometimes be wrong. Threading your way through a well-trodden but tiny pass in the rocks, the smallest datum shift can put you in dire danger. The men who erected transit markers like this one centuries ago knew that if they got it wrong, they might well be hung in the town square, which concentrated their minds on getting it dead right. A transit doesn’t purport to tell the whole story, but when you’re threading the bricks, all you need is to know you won’t hit them, so the transit cuts right to the chase.
In any case, it’s a lot easier to look at two objects lined up ahead of you than to respond to a virtual-reality screen – especially with a surge running. One of the arts of modern navigation is knowing when to revert to the ancient ways.