Here's where she begins the explanation of the power of the map:
Note the fun cartographic elements in the form of the globe in the heroine-captain's cabin... but that's not Earth, and with floating islands of land and flying, hyperspace-travelling sailing ships, this is a very different place than where we live:
I'd suggest starting at the beginning of the story and enjoying the whole thing. Avast mateys! Map-based Webcomic Ho!