If I were going out on a mapping trip to locate and make waypoints of structure then I'd mark EVERYTHING I saw. I'd mark what was on the banks if I could get out of the boat without sinking up in the mud. Years ago me and friends would put structure (trees) out ON THE BANKS...out of the water...for the crappie to spawn in. When the lakes filled the crappie didnt have any problems finding 'em either. I'd mark what I thought would be shallow AND what will be deeper. Remember, the crappie stage in and out of shallow waters. Cover is ALWAYS GOOD.