The PBS Community site has posted a really nice read on cartography - written by Johnathan White - the mapmaker for Pirates of the Burning Sea.  Here is a preview of the article:

Why Maps? Maps are a combination of sciences, art, history, and mythology. The cartography of early mapmakers was a form of art practiced by few in times past, and even fewer now. Almost all maps created today are the products of computers; either enhanced or supplemented by computers in someway shape or form, but not truly hand made. There are a number of aspects involved in this type of cartographer. Art, history, geography, mathematics, astronomy, astrology, use / practicality and personal involvement. All of these different aspects I will cover. But first, a question I am asked so often. Why maps? The answer is quite simple. Personal accomplishment. I could be a tradition artist and paint whatever my heart desires, draw the world around me, or create statues and sculptures of metal and stone. These I have done and tend to prefer the depth and complexities involved in the ancient practice of Portolan creation. The personal rewards and since of accomplishment of creating a piece of work that requires so many different skills is unsurpassed.

You can read the full article at this link (note: you will need to register and/or login to the PBS Community site first)