xkcd #3207: Bad Map Projection: Zero Declination
Title text:
‘The zero line in WMM2025 passes through a lot of population centers; I wonder what year the largest share of the population lived in a zone of less than 5° of declination,’ he thought, derailing all other tasks for the rest of the day.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3207/


Is this even a bad map projection? If you’re working with a compass this sounds pretty useful
Yeah, afaik, there’s need for accounting for magnetic North difference from North when navigating even on foot, so it’s stated on the map with small enough scale