I think this is such a fantastic idea. This is one of the last pages in my Hobonichi Weeks, and it’s ingenious. I am sure there are loads of measurement apps, but this for me is the best way of visualising things. You measure your foot, arm, stride length, or other things you may have with you at all times (coins, paper money, bottle of water) and then use those measurements when you need to check how big something is when you are out and about without a tape measure.
People are different in the way they like to measure things, calculate things or interpret directions. I am definitely not a ‘turn left, walk for 200 metres then turn right type of person’. I much prefer someone to say ‘go that way and look out for the green building’. So when it comes to measurements, I always measure things in my head in relation to a concrete object that I can visualise.