The main goal of a map is to facilitate the transfer of knowledge between the map author and reader. It's important to communicate important information, but we must also attract and retain the viewer's interest. After all, if no one looks at your map, your information doesn't get communicated at all! The design of your map, like a well-articulated argument, can either support or hinder your message.
The design is a process, with specific strategies and benchmarks to help us achieve clear communication. Bad design is usually easy to spot—we can quickly point to why or how something isn't working. Good design can be harder to identify. If all the elements are working together as they should, everything is seamless.
In mapping, we work with the trinity of balance, harmony, and unity. Balance is the art of placing elements around the page so that they don't draw the eye unnaturally to one side or the other. While symmetry is seldom possible (particularly with maps...