The map will help you keep track of your travels, where you are and where you are headed next. Sometimes you'll be working on a series of journeys that are progressing in a particular order and, all of a sudden, you'll get lost or pulled into a seemingly unrelated journey. If you have a map, you'll be able to get back to where you were once the new information is assimilated. The reason you might get hauled off course is that some new event might be happening in your life and the Inner World, your guides, want to help you with it. Once that is done, you'll be able to get back to your journey series, and that will be more easily accomplished if you have a map.
Sometimes the shape of your Inner Landscape alone will give you a clue about something you're working on. If you're ill, the land mass might take the shape of the body organ that is effected the most by the illness. Or the color that you see might be related to a specific chakra. You might be walking a path and come to an abyss that blocks your forward progress and later understand that the reason you were blocked is because there was a huge separation between your conscious and subconscious mind levels. There will be clues everywhere, learn to decipher them.