While planning the 50-for-50 walk, I built a custom routing tool that took in a plain-text route file and generated whatever I needed: a .gpx for my watch, a .kml for my phone's navigation, an HTML Street View preview to spot-check the route. In that spirit, I started wondering: could it also generate a printable reference card? Something I could fold up and keep in my pocket.
Version one generated an index card-sized map. I printed it, got out the scissors, trimmed it down — and threw away most of the paper. That's when it hit me how absurd the index card idea was. It was more work for something less useful, all to meet some arbitrary size requirement.
So the goal shifted: pack as useful a reference as possible onto two pages — a single sheet, double-sided. No cutting required. That became the challenge, and pocketmap is the result.
Two Sheets, Two Jobs
pocketmap takes the same plain-text .pois file used by geoassist and generates a two-page PDF:
pocketmap day1.pois > day1.pdf
Page two is the simpler one: a waypoint table showing each stop, its cumulative distance from the start, and the distance to the next stop. Combined with a distance reference chart (centimeters on the printed map → km and miles), it doubles as a checklist. With six waypoints spaced 2–4 miles apart, a 17-mile day starts to feel doable — just a short list of stops to check off. Shira — a seasoned skeptic of my "this will make things easier" projects — actually used it, treating the waypoint table as a table of contents for the day. That's when I knew I was really onto something.
The 1 cm Rule
Page one is the map, and it's more useful than it first appears. The map is scaled so that the entire route fits on a single page, always expressed in a clean ratio: 1 cm = 1 km, or 1 cm = 2 km, or whatever it takes to fit. The scale bar is on the page.
That simple cm rule connects directly to UTM coordinates, which are printed along the edges of the map just like a USGS topographic quad. A GPS device — phone, Garmin watch, or an InReach you're already carrying for messaging — can display your current UTM coordinates. Find those numbers on the map edge, locate the intersection, and you know exactly where you are.
The useful part: this works without a data connection. Your GPS receiver uses satellites, not cell towers. You can be somewhere with no signal and still find yourself on the map in seconds. If UTM is new to you: it initially looks complex, but it's actually straightforward — and a remarkably simple way to jump between a paper map and a digital device. This video is a quick intro.
I carry a small fresnel lens with centimeter markings along the edge. With the map, that lens becomes a measuring tool: lay it down, count centimeters, multiply by the scale. I can estimate how far I've come, or how far to the next stop, in a few seconds.
How It Actually Went
Honestly, the map was more of a satisfying curiosity than a critical tool on our trip. We were in Knoxville, not the backcountry — if something went wrong, we would call an Uber. But there's something genuinely satisfying about making the leap from digital coordinates to paper in a few moments, and having something physically in my pocket that represents the day ahead.
One thing I hadn't anticipated: the fixed scale. On your phone, you zoom in and out constantly, always seeing the same 2–3 inches of map regardless of zoom level. The printed map doesn't do that. At 1 cm = 1 km, you always see the same stretch of ground. That consistency helps maintain a sense of the whole day — something that gets lost the moment you zoom in on your phone.
One real limitation: the map is useless at micro-navigation. Come to a trail fork — left or right? The scale is way too zoomed out to help. For that, you need your phone.
Low Effort, High Value
If you're using geoassist to build your .pois file, the PDF is a free byproduct. Print it, fold it, put it in your pocket. It won't replace your phone — but it gives you something your phone can't: a fixed, at-a-glance view of the whole day that works anywhere.
Download Pocketmap
pocketmap is free to use and modify. Source code on GitHub: github.com/benjisimon/code/tree/main/pocketmap
