Rock map of Scotland

Harry Jefferies shared his grandfather’s 30-year project:

My grandpa who is 85 started making this rock map of Scotland in 1992. He collected rocks during amateur geology trips over 30 years. He says it had to be geologically correct and also aesthetically pleasing. He asked if I could share online as He wants to go viral so please share

Thirty years. I’m a sucker for slow data collection and physical visualization.