Easy Map Making

Crap, I need a map, and I need it by tonight.

My players are about to sneak into a pirate den and attempt to steal a ship. They have no idea how to sail a ship, but luckily for them, there is a good chance that the ship will be out to sea anyway. As a consolation, the pirates' treasure horde, if they find it, will contain books on sailing and a map of the local coastal area.

I have a hex map, made with Hexographer, that I use for overland travel, but I wanted to give them something more in-universe for their characters to find. So how do I go about making a map that looks somewhat realistic?

Because I want realistic maps with believable geography, the first thing I do when making any campaign map is consult Google Earth for an interesting location. For this map, I turned South America upside down:

Then I messed with the contrast to make it more traceable and printed out a grayscale version. I made a makeshift lightbox by putting a lamp under a glass table so I could easily trace the outline of the coast. There is a sheet of white printer paper over the printout of the map.

I traced the map:

As you can see, I moved the Falkland Islands up and to the right and fudged the coastline a little bit. I also added an archipelago extending from the tip of Tierra del Fuego almost to the South Sandwich Islands. Hopefully at this point it is already unrecognizable as upside-down Patagonia.

The next step involved roughing up the map a little:

The thing that makes this post great is the beautiful photography. Next I scanned it and opened it in GIMP (Photoshop? Aren't you fancy). I'm going for something similar to a medieval portolan chart:

I fiddled with the brightness and contrast, used the scissor tool to select the land areas, and colorized them. Next I added some rhumb lines and filled in a few cities. Because I'm lazy and didn't want to come up with 50 city names on the fly, I decided that at some point they will learn that the map is magical and perhaps events, spells, or interactions will reveal hidden names and rhumb lines in the future. Here's the map:

I used miles and an approximate km equivalent because this is a roll20 game and my players are in multiple countries. I debated using an in-world measurement (leagues? li? let's just keep it simple). Not brilliant, but good enough, right? With a little effort, you could do something great with this method.