Learning out Loud in Milwaukee, WI

Open Source Cartography

During my sabbatical, I came upon a podcast called Very Expensive Maps by way of Jason Kottke. It’s hosted by Evan Applegate, cartographer who talks to better cartographers.” It quickly landed among my favorite must-listen-to podcasts alongside Las Culturistas, How Did This Get Made, and The New Bazaar. The first episode I listened to on a long drive featured Melinda Clarke and Deborah Young Monk, makers of The Melbourne Map, a 1990 tourism map of Melbourne, Australia. They had this amazing story about trying to get this map made that involved flying above the city in balloons, finding counterfeits for sale, and how they made decisions about what to include. The episode was a good reminder of why map making is an inherently

The next episode was three Venn Diagrams converging to make a perfect circle for my interests: public service, cartography, and open source. Tom Patterson, who made his entire career creating maps for the US National Parks Service and is also famous for leadership on the Natural Earth data set and his amazing collection of blog posts, tutorials, and resources for making shaded relief maps that are useful and beautiful.

Most people have encountered some kind of shaded relief map. Google’s Terrain base layer has a hillshade. It puts texture on the landscape by lightly shading the side of hills away from “the sun” at a standard angle. It’s not a 3D map, though, in the way that a cartographer like Patterson would make it. Mount Everest on Google, for example, looks fine. Clearly it’s a big mountain, a steep one, densely surrounded by other big steep mountains. Patterson’s Everest gives you a better sense of the mountain’s physical features, its prominence, and the landscape.

Making a 3D map like Patterson’s takes years of skill development to create, even with today’s tools. I appreciated his perspective on map making: “Right now we’re in the golden age of cartography.” You don’t need all the time, materials, and training required to make maps like they did before the dawn of GIS. Listening to these two interviews inspired me to start making my own maps.


The open source geographic information system QGIS is an extremely powerful piece of software. It’s been around since 2002 but really picked up development after a major rewrite in 2018. It doesn’t have the extensive data network that ESRI’s ArcGIS has built in, but it can connect to many web services, including Arc’s. Like many good open source projects, QGIS is also extremely extensible, and there are plugins out there that bring in many features and tools it lacks out of the box.

Public data

A lot of the data you need to make a good map is easy to find and open source if not public domain.

You can make a pretty decent looking map without having to pay for any subscription service.

Basemaps and imagery

You can certainly create your own imagery using Digital Elevation Model (DEM) files or land cover data if you want to have more control over how you visualize terrain or land cover. If you want to save yourself some work or don’t need that much control over the visualization, ESRI, Google, Stamen, Open Streetmap all make great basemaps to use, and there are others out there. These are particularly good options, in my extremely novice opinion, if you want satellite data and don’t particularly care how fresh it is.

A really satisfying thing about making your own imagery, though, is that you get to play around with the data. You can exaggerate elevation if you want, or change the angle and azimuth of the “sun” in your hillshade. I’ve been tinkering with the DEM-based hillshade on a map I’m working on and it’s a lot of fun to try to balance “realism” against emphasizing what I want the reader to see.

Layout and formatting

For a map I’m working on for a Christmas gift, I modeled the colors, symbology, and labeling very closely off of the topographic “7.5 Minute Series” made by the USGS. Many US government agencies make their design specs public. These are good starting points because they’ve made intentional decisions about scale, page size, etc. that make them useful. The 7.5 Minute series also has thousands maps across the US to reference for the decisions I had to make for own: Which communities to show, streets to name, where to place labels on bodies of water, how prominent to make transportation lines, etc.


The challenge with mapping is how you choose what to show. The more you try to cram onto the canvas, the more you sacrifice interpretation. Maps are inherently rhetorical objects. They present arguments to viewers about what’s important to know right here, wherever that may be.

I’m making a map right now for a Christmas gift and decided to use Google’s Terrain basemap. It has a gentle hillshade with no labels or colors for other land features. It’s good enough to provide texture without distracting from the information I want to show, which was the watershed and public land boundaries, and topographic contours of a specific area of Wisconsin. I also strayed from the more rigid 7.5 minute distance boundary because I wanted to show more of the area around the map center. Predictable distance was less important than predictable wall space.

I’ll post a PDF after I give the gift. Don’t want to spoil it.