How Long Is the Coast of Britain? (1967)

Link to a pdf file that you don't need an institutional login for.

I did an activity in a basic maths class based on this paper years ago. Each student had an A3 map of the main island of the UK. Some set their compasses to 5cm radius and counted the number of radii around the island. Others tried 2.5cm, and 1cm and half a cm. Worked ok, good lesson.

https://en.wikipedia.org/wiki/Coastline_paradox

where the sampling rate affects distance measured

this is also why the GPS on your watch will reports different distances the more frequently it samples, ie. once per second vs once per every few seconds, think curves becoming diagonal lines

it's also why they measure official distances using a wheel on a stick