Cais is a series of pocket walking guides published by a walking trust in Braga. There are three so far: the Gerês, in the mountains to the north; the coast, along the boardwalks through the dunes; and Gaia, across the river from Porto. Each one is made to live in the side pocket of a backpack, and most of them do.

One line per walk

Every walk is drawn as a single orange line. The maps show only what you need on the day: the line, the climbs, where to find water and where the bus stops. Everything else came off.

I drew the maps by hand from the trust’s GPS tracks, then simplified them until each bend in the line matched a bend you can see from the path. After a test walk in the rain, the line went from 1 mm to 2 mm thick, because the thin one vanished on a damp page.

Made for a pocket

The guides are small and plain on purpose. The decisions that mattered most:

• A6 pages, so a guide fits the side pocket of most backpacks.

• A sewn spine, so it opens flat on a rock and stays open.

• Uncoated paper that takes a pencil note.

• One walk per spread, a photograph on the left and the map on the right.

The photographs are there for recognition, not decoration. A cobbled lane where the route turns looks the same on the page as it does in front of you, and that is how you know you’re still on the walk.

A box for members

Members of the trust get each new guide in a grey box with a folded map of the whole region, so they can see how the walks connect. A tote printed with all three routes comes with the first box.

The guides are also sold in bookshops and from a wire rack on café counters along the coast, where walkers stop anyway. The rack was the trust’s idea, and it now sells more guides than the bookshops.