Amazing but true!


Yeah so today I learned that all the mountains on those sectional charts are shaded as if the sun were setting in the northwest. Amazing, huh!

Wow!!! I thought you were joking, crazy, bored etc. but sure enough it's true! It's almost midnight and I just had to look at a sectional.

Here's a little something stolen from my last career as a cartographer / GIS analyst:

The reason the mountains are shaded as if the sun was shining from the northwest is because, due to history and at least in western cultures, our eyes are trained to read from top-left to bottom right. Therefore, when terrain is illuminated from the top left, it is quickly processed by our brains in the manner cartographers intend.

Try this: view a VFR Sectional (or any other like map) in an area that is familiar to you, except upside down to simulate as southern sun exposure (flatland folks.. sorry I cant help ya, find a new area to look at). If you do this, the valleys USUALLY appear as ridges and mountain ridges appear as valleys.

when I used to produce shaded terrain computer 'models', I used to put the sun at about 315 degrees, and about 60 degrees up from the horizon.

I hope this is the nerdiest thing I ever post on this forum

Why do they use yellow for towns/cities? I learned the hard way it's next to impossible to see them on sectionals at night with red light. I wanna use jet route charts when I grow up
LOL no they aren't yellow, they are "lit up" - if your city is yellow you need to move, Iain! Bad air!