I got a navigation type map of the lake I fish (Wilson Lake)  Im trying to locate areas thhat would be spawning flats and then find deep water drop offs near there.   what do I need to look for on the map to find these areas?  One thing I notice is that on the map it looks like some areas are 58' deep but I was there last week and on my depthfinder it shows 20-25' deep.   whats up with the depth shown on the map?? Are  they measuring from somewhere  other than water surface??  Im sure that others have the same kind of questions about how to read the map to find good spots.  Please help?????

Is it possible the number you are looking at is an elevation ring?  This would be showing you the elevation above sea level, and usually would be in increments of 10-20-40 or something like that.  

I thank the Army for my topo map reading skills, but it does take some time to figure it out.  I'm better at reading maps than I am knowing where fish will be ON them, so I dont want to steer you in the wrong direction, but hopefully I can help you get your feet wet, so to speak.  Try to find something online that may help, like this:

http://www.compassdude.com/topographic-maps.shtml