I don't usually put keys on my cave maps unless I've got a big blank space to fill, but I regularly give my surveys to landowners who are not familiar with cave symbols. So I usually include a key on a separate sheet. Does anyone have a nice, thorough, explanatory key that could be used for this purpose? I would like to have a clean-looking way to teach landowners how to read a map, but my work is low-tech, hand drawn stuff.

Several online keys could be stolen, but I can't find any easy-to-grasp ones at good resolution.

therion.speleo.sk/wiki/lib/exe/fetch.../therion_symbols_20130407_.pdf

This is the official UIS symbol set

http://www.carto.net/neumann/caving/cave-symbols/