Here is some helpful information about reading maps and finding fish when fresh water fishing. Don't know if I can post this but I am showing the link.
http://www.fishinghotspots.com/library/chapter_5_1.html

Part 1

Finding Fish on a Map
Fish spend most of their time in sanctuaries--holed up where they are safe and comfortable(adequate oxygen and acceptable temperature). Except in extreme cases, fish sanctuaries are the deepest pockets in a defined area that includes access to food. A fish's instinctive behavior limits the boundaries of its territory.
One theory of fish behavior contends all species of fish move from their sanctuaries to areas where they actively feed. Hunger triggers movement. When their stomachs are full, they return to their sanctuaries.
Another theory maintains that weather and light activate fish movement. Low pressure storm fronts stimulate fish to move and feed. When the front passes and the weather clears, fish are less active and are found tight to cover. Regardless of what causes fish movement, expect them to move regularly within a set territory.

Light and weather influence the movement and feeding patterns of fish


Another principle of fish behavior is all movement takes place along defined routes. Fish orient themselves with certain features of their underwater environment and travel set pathways between feeding areas and holding areas (see image below).