This is a broad area, and I doubt a series of posts will do more than confuse you.
Two good things:
1) Once you get the knack of it--and there isn't much to getting the knack--it's pretty simple to read a topo map.
2) What you're setting out to do is a VERY useful skill that will change the way you view maps and even look at landscapes.
Check out
this site for a great introduction.
Basically, a topo map is a highly accurate map with contour lines all over it. Contour lines tell you a remarkable amount of information: the closer lines are together, the steeper the terrain; the farther apart they are, the more gentle the terrain.
Here are some things you can learn right away from topo maps:
1. How vertical distance affects total distance. On a regular map, the distance between two points is pretty simple to measure. A topo map can warn you that you need to add more miles to a trip just from all the up and down in between.
2. Where water flows and is likely to be found.
3. Here's a hill: what's the easiest way to climb it?
I know that many people first approaching topo maps are confused by the contours. I'd like to share a concept with you that made me instantly understand how they work.
We'll create a virtual topo map together.
Take an imaginary lump of clay and a bucket (I should point out that when I learned, we did this with real clay and water, but anyone can do this as a thought experiment).
Mold the lump of clay into a mountain, and place it dead center into the bucket.
Draw the outline of the base of the mountain on a sheet of paper.
Add one inch of water to the bucket.
Draw the outline of the "shoreline" on your sheet of paper, keeping the position the same.
Add a second inch of water to the bucket.
Draw *this* shoreline on your sheet of paper....
Keep adding an inch of water at a time, and drawing the new shoreline, until the mountain is completely covered.
The result? A topo map. You'll instantly see how steeper sides have closer lines, and how gentler slopes have lines spread further apart. The distance between each line represents one inch of water.
A topo map is identical: the distance between the lines is measured in vertical feet, not inches of water. But the concept is the same.
Here's a neat thing: you can reverse the process I described, and you can create a three-dimensional clay model of a mountain with a little bit of patience and a topo map.
The trick is to start doing this in your head, of course, and not working with clay and buckets!
As you advance in your comfort, you'll start to see how the legend works to give you even more data (hashed lines represent depressions below sea level, if you want to anticipate where water can form, structures and buildings, etc.).
Because the USGS has standardized topo maps, you can make some simple rulers at home (or buy them at better equipped sporting good stores) that allow you to take very accurate measurements, plan waypoints, etc.
I salute your decision not to rely on GPS alone. I think GPS is the coolest thing since sliced bread...but GPS really shines when you understand basic cartography and navigation principles.
