What do the various patrol icons mean?

destiny

As it turns out, there's a post on Reddit with an image that answers this nicely:

enter image description here

Related

Is there a compelling reason to level crafting in GW2 if my character is already L80?
LeBlanc Combos?
Decrypting armour engrams with different classes
What does the grey arrow on the minimap mean?
Can no longer see the crosshair or hotbar
Are the earlier expansions required for The Taken King?
Power Generator vs Reactor, are they even different?
How can you wake an incapacitated guard?
Where does The Phantom Pain store its save-game data on PC?
Are there Secret Rooms in Greed Mode?
How to use the minecraft 1.9 "Passengers" tag?
Where can I get leather?