Today a friend of mine made me realize that roundabouts have “perfect” road markings around them and i started wandering how a machine would go about making a circle without a compass-like system. So i tried google but every result led to either a janky home made compass or some sort of hand-drawing technique. I assume it should be possible to draw a circle knowing the radius in an analog system without a compass but i can’t figure out how. Plus i don’t know how the physical structure of a roundabout is made to be round and that is even weirder to think about.
TLDR: How are roundabouts and round road markings made?
Have you seen these people with a weird tripod on construction sites ? They’re surveyor and have tools allowing them to do very precise measure (A guy told me that one of the coolest things he has done was to make sure railway track were aligned below 1mm on both side of 2 km bridge to build) I would expect that drawing a circle isn’t that complicated.
Then the rest is usual road construction, add temporary marking, close the road, do the measurement and build the roundabout