Liberating Map Symbols
There is an undeniable charm to the symbols and patterns in many historic maps. So much so, that these styles have come to represent maps of antiquity in general and are often repurposed into graphic design for fantasy and role playing maps. While the reinterpretations of these styles are great, there is a richness to the originals that shouldn’t be overlooked. For anyone possessing the skills needed to draw these symbols on their own, kudos. For the rest of us, liberating elements directly off old maps into symbol and style libraries for common design software makes it much easier to create designs informed by an older aesthetic.
The workflow in general is relatively simple: isolate and crop selected symbols or patterns in a high resolution scan of your map; process the new picture in image editing software like GIMP or Photoshop to get a clean looking PNG; open the new PNG in a graphics application like Inkscape or Adobe Illustrator and use their built in auto trace tools to convert the PNG into an SVG. PNGs are great for basic clipart as they have a transparent background, SVGs are full vectorized version of you symbol allowing you to control fill colors, line thicknesses, and even re edit the shape of the symbol itself.
If these terms are new to you, don't worry, there's lots of help online! You can find tutorials for using the image trace tools in Illustrator and Inkscape on Youtube. They cover the basics, but be prepared to spend some time trying different options for each tool. Your image to vector results will vary depending on the specifics of the input image (DPI, color, bit depth).
Crop and export
Crop your selected symbol from the main image and save as a new image file.
Grayscale and add contrast
If your scan was full color and your end goal is a simple single layer vector graphic then convert your cropped image to grayscale. Otherwise leave the image full color. Using the Levels or Curves tools here can help with a nice crisp high contrast image to work from.
Clean and transparent
Using the Photoshop Brush tool with white fill, remove all unwanted parts of the image. Be careful to clean up even the smallest specks in the white areas. The Posterize tool can sometimes help define edge pixels on lower resolution scans.
If you just need a transparent image you can use the select tool to copy your edited image to a new Photoshop layer with a blank background. Save as a new PNG.
If you want to create a vector file you’ll need to open the cleaned image in Illustrator (or Inkscape) and use the Image Trace menu. Sketched Art is a good choice for the output, but you can also try Silhouettes or Shades of Gray.
David Medeiros - Geospatial Reference and Instruction Specialist, Stanford Libraries.
I’ve been involved in the world of maps one way or another for the past two and half decades, working a variety of GIS and cartographic jobs. At the Stanford Geospatial Center I teach students how to use maps as analysis and communication tools in their studies and research. Map design and aesthetics is a particular interest of mine and as a habitual maker of custom maps and terrain sculptures, I find the content in our collection of historic maps constantly inspiring and enviable.